Storm SQL language

Storm SQL uses Apache Calcite to parse and evaluate the SQL statements. Storm SQL also adopts Rex compiler from Calcite, so Storm SQL is expected to handle SQL dialect recognized by Calcite's default SQL parser.

The page is based on Calcite SQL reference on website, and removes the area Storm SQL doesn't support, and also adds the area Storm SQL supports.

Please read Storm SQL integration page first to see what features Storm SQL supports.

Grammar

Calcite provides broader SQL Grammar. But Storm SQL is not database system and handles streaming data, so only subset of grammar is supported. Storm SQL doesn't redefine SQL Grammar and just utilize the parser Calcite provided, so SQL statements are still parsed based on Calcite's SQL Grammar.

SQL grammar in BNF-like form.

statement:
      setStatement
  |   resetStatement
  |   explain
  |   describe
  |   insert
  |   update
  |   merge
  |   delete
  |   query

setStatement:
      [ ALTER ( SYSTEM | SESSION ) ] SET identifier '=' expression

resetStatement:
      [ ALTER ( SYSTEM | SESSION ) ] RESET identifier
  |   [ ALTER ( SYSTEM | SESSION ) ] RESET ALL

explain:
      EXPLAIN PLAN
      [ WITH TYPE | WITH IMPLEMENTATION | WITHOUT IMPLEMENTATION ]
      [ EXCLUDING ATTRIBUTES | INCLUDING [ ALL ] ATTRIBUTES ]
      FOR ( query | insert | update | merge | delete )

describe:
      DESCRIBE DATABASE databaseName
   |  DESCRIBE CATALOG [ databaseName . ] catalogName
   |  DESCRIBE SCHEMA [ [ databaseName . ] catalogName ] . schemaName
   |  DESCRIBE [ TABLE ] [ [ [ databaseName . ] catalogName . ] schemaName . ] tableName [ columnName ]
   |  DESCRIBE [ STATEMENT ] ( query | insert | update | merge | delete )

insert:
      ( INSERT | UPSERT ) INTO tablePrimary
      [ '(' column [, column ]* ')' ]
      query

update:
      UPDATE tablePrimary
      SET assign [, assign ]*
      [ WHERE booleanExpression ]

assign:
      identifier '=' expression

merge:
      MERGE INTO tablePrimary [ [ AS ] alias ]
      USING tablePrimary
      ON booleanExpression
      [ WHEN MATCHED THEN UPDATE SET assign [, assign ]* ]
      [ WHEN NOT MATCHED THEN INSERT VALUES '(' value [ , value ]* ')' ]

delete:
      DELETE FROM tablePrimary [ [ AS ] alias ]
      [ WHERE booleanExpression ]

query:
      values
  |   WITH withItem [ , withItem ]* query
  |   {
          select
      |   selectWithoutFrom
      |   query UNION [ ALL ] query
      |   query EXCEPT query
      |   query INTERSECT query
      }
      [ ORDER BY orderItem [, orderItem ]* ]
      [ LIMIT { count | ALL } ]
      [ OFFSET start { ROW | ROWS } ]
      [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ]

withItem:
      name
      [ '(' column [, column ]* ')' ]
      AS '(' query ')'

orderItem:
      expression [ ASC | DESC ] [ NULLS FIRST | NULLS LAST ]

select:
      SELECT [ STREAM ] [ ALL | DISTINCT ]
          { * | projectItem [, projectItem ]* }
      FROM tableExpression
      [ WHERE booleanExpression ]
      [ GROUP BY { groupItem [, groupItem ]* } ]
      [ HAVING booleanExpression ]
      [ WINDOW windowName AS windowSpec [, windowName AS windowSpec ]* ]

selectWithoutFrom:
      SELECT [ ALL | DISTINCT ]
          { * | projectItem [, projectItem ]* }

projectItem:
      expression [ [ AS ] columnAlias ]
  |   tableAlias . *

tableExpression:
      tableReference [, tableReference ]*
  |   tableExpression [ NATURAL ] [ LEFT | RIGHT | FULL ] JOIN tableExpression [ joinCondition ]

joinCondition:
      ON booleanExpression
  |   USING '(' column [, column ]* ')'

tableReference:
      tablePrimary
      [ [ AS ] alias [ '(' columnAlias [, columnAlias ]* ')' ] ]

tablePrimary:
      [ [ catalogName . ] schemaName . ] tableName
      '(' TABLE [ [ catalogName . ] schemaName . ] tableName ')'
  |   [ LATERAL ] '(' query ')'
  |   UNNEST '(' expression ')' [ WITH ORDINALITY ]
  |   [ LATERAL ] TABLE '(' [ SPECIFIC ] functionName '(' expression [, expression ]* ')' ')'

values:
      VALUES expression [, expression ]*

groupItem:
      expression
  |   '(' ')'
  |   '(' expression [, expression ]* ')'
  |   CUBE '(' expression [, expression ]* ')'
  |   ROLLUP '(' expression [, expression ]* ')'
  |   GROUPING SETS '(' groupItem [, groupItem ]* ')'

windowRef:
      windowName
  |   windowSpec

windowSpec:
      [ windowName ]
      '('
      [ ORDER BY orderItem [, orderItem ]* ]
      [ PARTITION BY expression [, expression ]* ]
      [
          RANGE numericOrIntervalExpression { PRECEDING | FOLLOWING }
      |   ROWS numericExpression { PRECEDING | FOLLOWING }
      ]
      ')'

In merge, at least one of the WHEN MATCHED and WHEN NOT MATCHED clauses must be present.

In orderItem, if expression is a positive integer n, it denotes the nth item in the SELECT clause.

An aggregate query is a query that contains a GROUP BY or a HAVING clause, or aggregate functions in the SELECT clause. In the SELECT, HAVING and ORDER BY clauses of an aggregate query, all expressions must be constant within the current group (that is, grouping constants as defined by the GROUP BY clause, or constants), or aggregate functions, or a combination of constants and aggregate functions. Aggregate and grouping functions may only appear in an aggregate query, and only in a SELECT, HAVING or ORDER BY clause.

A scalar sub-query is a sub-query used as an expression. If the sub-query returns no rows, the value is NULL; if it returns more than one row, it is an error.

IN, EXISTS and scalar sub-queries can occur in any place where an expression can occur (such as the SELECT clause, WHERE clause, ON clause of a JOIN, or as an argument to an aggregate function).

An IN, EXISTS or scalar sub-query may be correlated; that is, it may refer to tables in the FROM clause of an enclosing query.

selectWithoutFrom is equivalent to VALUES, but is not standard SQL and is only allowed in certain conformance levels.

Keywords

The following is a list of SQL keywords. This list is also from Calcite SQL reference. Reserved keywords are bold.

A, ABS, ABSOLUTE, ACTION, ADA, ADD, ADMIN, AFTER, ALL, ALLOCATE, ALLOW, ALTER, ALWAYS, AND, ANY, ARE, ARRAY, AS, ASC, ASENSITIVE, ASSERTION, ASSIGNMENT, ASYMMETRIC, AT, ATOMIC, ATTRIBUTE, ATTRIBUTES, AUTHORIZATION, AVG, BEFORE, BEGIN, BERNOULLI, BETWEEN, BIGINT, BINARY, BIT, BLOB, BOOLEAN, BOTH, BREADTH, BY, C, CALL, CALLED, CARDINALITY, CASCADE, CASCADED, CASE, CAST, CATALOG, CATALOG_NAME, CEIL, CEILING, CENTURY, CHAIN, CHAR, CHARACTER, CHARACTERISTICTS, CHARACTERS, CHARACTER_LENGTH, CHARACTER_SET_CATALOG, CHARACTER_SET_NAME, CHARACTER_SET_SCHEMA, CHAR_LENGTH, CHECK, CLASS_ORIGIN, CLOB, CLOSE, COALESCE, COBOL, COLLATE, COLLATION, COLLATION_CATALOG, COLLATION_NAME, COLLATION_SCHEMA, COLLECT, COLUMN, COLUMN_NAME, COMMAND_FUNCTION, COMMAND_FUNCTION_CODE, COMMIT, COMMITTED, CONDITION, CONDITION_NUMBER, CONNECT, CONNECTION, CONNECTION_NAME, CONSTRAINT, CONSTRAINTS, CONSTRAINT_CATALOG, CONSTRAINT_NAME, CONSTRAINT_SCHEMA, CONSTRUCTOR, CONTAINS, CONTINUE, CONVERT, CORR, CORRESPONDING, COUNT, COVAR_POP, COVAR_SAMP, CREATE, CROSS, CUBE, CUME_DIST, CURRENT, CURRENT_CATALOG, CURRENT_DATE, CURRENT_DEFAULT_TRANSFORM_GROUP, CURRENT_PATH, CURRENT_ROLE, CURRENT_SCHEMA, CURRENT_TIME, CURRENT_TIMESTAMP, CURRENT_TRANSFORM_GROUP_FOR_TYPE, CURRENT_USER, CURSOR, CURSOR_NAME, CYCLE, DATA, DATABASE, DATE, DATETIME_INTERVAL_CODE, DATETIME_INTERVAL_PRECISION, DAY, DEALLOCATE, DEC, DECADE, DECIMAL, DECLARE, DEFAULT, DEFAULTS, DEFERRABLE, DEFERRED, DEFINED, DEFINER, DEGREE, DELETE, DENSE_RANK, DEPTH, DEREF, DERIVED, DESC, DESCRIBE, DESCRIPTION, DESCRIPTOR, DETERMINISTIC, DIAGNOSTICS, DISALLOW, DISCONNECT, DISPATCH, DISTINCT, DOMAIN, DOUBLE, DOW, DOY, DROP, DYNAMIC, DYNAMIC_FUNCTION, DYNAMIC_FUNCTION_CODE, EACH, ELEMENT, ELSE, END, END-EXEC, EPOCH, EQUALS, ESCAPE, EVERY, EXCEPT, EXCEPTION, EXCLUDE, EXCLUDING, EXEC, EXECUTE, EXISTS, EXP, EXPLAIN, EXTEND, EXTERNAL, EXTRACT, FALSE, FETCH, FILTER, FINAL, FIRST, FIRST_VALUE, FLOAT, FLOOR, FOLLOWING, FOR, FOREIGN, FORTRAN, FOUND, FRAC_SECOND, FREE, FROM, FULL, FUNCTION, FUSION, G, GENERAL, GENERATED, GET, GLOBAL, GO, GOTO, GRANT, GRANTED, GROUP, GROUPING, HAVING, HIERARCHY, HOLD, HOUR, IDENTITY, IMMEDIATE, IMPLEMENTATION, IMPORT, IN, INCLUDING, INCREMENT, INDICATOR, INITIALLY, INNER, INOUT, INPUT, INSENSITIVE, INSERT, INSTANCE, INSTANTIABLE, INT, INTEGER, INTERSECT, INTERSECTION, INTERVAL, INTO, INVOKER, IS, ISOLATION, JAVA, JOIN, K, KEY, KEY_MEMBER, KEY_TYPE, LABEL, LANGUAGE, LARGE, LAST, LAST_VALUE, LATERAL, LEADING, LEFT, LENGTH, LEVEL, LIBRARY, LIKE, LIMIT, LN, LOCAL, LOCALTIME, LOCALTIMESTAMP, LOCATOR, LOWER, M, MAP, MATCH, MATCHED, MAX, MAXVALUE, MEMBER, MERGE, MESSAGE_LENGTH, MESSAGE_OCTET_LENGTH, MESSAGE_TEXT, METHOD, MICROSECOND, MILLENNIUM, MIN, MINUTE, MINVALUE, MOD, MODIFIES, MODULE, MONTH, MORE, MULTISET, MUMPS, NAME, NAMES, NATIONAL, NATURAL, NCHAR, NCLOB, NESTING, NEW, NEXT, NO, NONE, NORMALIZE, NORMALIZED, NOT, NULL, NULLABLE, NULLIF, NULLS, NUMBER, NUMERIC, OBJECT, OCTETS, OCTET_LENGTH, OF, OFFSET, OLD, ON, ONLY, OPEN, OPTION, OPTIONS, OR, ORDER, ORDERING, ORDINALITY, OTHERS, OUT, OUTER, OUTPUT, OVER, OVERLAPS, OVERLAY, OVERRIDING, PAD, PARAMETER, PARAMETER_MODE, PARAMETER_NAME, PARAMETER_ORDINAL_POSITION, PARAMETER_SPECIFIC_CATALOG, PARAMETER_SPECIFIC_NAME, PARAMETER_SPECIFIC_SCHEMA, PARTIAL, PARTITION, PASCAL, PASSTHROUGH, PATH, PERCENTILE_CONT, PERCENTILE_DISC, PERCENT_RANK, PLACING, PLAN, PLI, POSITION, POWER, PRECEDING, PRECISION, PREPARE, PRESERVE, PRIMARY, PRIOR, PRIVILEGES, PROCEDURE, PUBLIC, QUARTER, RANGE, RANK, READ, READS, REAL, RECURSIVE, REF, REFERENCES, REFERENCING, REGR_AVGX, REGR_AVGY, REGR_COUNT, REGR_INTERCEPT, REGR_R2, REGR_SLOPE, REGR_SXX, REGR_SXY, REGR_SYY, RELATIVE, RELEASE, REPEATABLE, RESET, RESTART, RESTRICT, RESULT, RETURN, RETURNED_CARDINALITY, RETURNED_LENGTH, RETURNED_OCTET_LENGTH, RETURNED_SQLSTATE, RETURNS, REVOKE, RIGHT, ROLE, ROLLBACK, ROLLUP, ROUTINE, ROUTINE_CATALOG, ROUTINE_NAME, ROUTINE_SCHEMA, ROW, ROWS, ROW_COUNT, ROW_NUMBER, SAVEPOINT, SCALE, SCHEMA, SCHEMA_NAME, SCOPE, SCOPE_CATALOGS, SCOPE_NAME, SCOPE_SCHEMA, SCROLL, SEARCH, SECOND, SECTION, SECURITY, SELECT, SELF, SENSITIVE, SEQUENCE, SERIALIZABLE, SERVER, SERVER_NAME, SESSION, SESSION_USER, SET, SETS, SIMILAR, SIMPLE, SIZE, SMALLINT, SOME, SOURCE, SPACE, SPECIFIC, SPECIFICTYPE, SPECIFIC_NAME, SQL, SQLEXCEPTION, SQLSTATE, SQLWARNING, SQL_TSI_DAY, SQL_TSI_FRAC_SECOND, SQL_TSI_HOUR, SQL_TSI_MICROSECOND, SQL_TSI_MINUTE, SQL_TSI_MONTH, SQL_TSI_QUARTER, SQL_TSI_SECOND, SQL_TSI_WEEK, SQL_TSI_YEAR, SQRT, START, STATE, STATEMENT, STATIC, STDDEV_POP, STDDEV_SAMP, STREAM, STRUCTURE, STYLE, SUBCLASS_ORIGIN, SUBMULTISET, SUBSTITUTE, SUBSTRING, SUM, SYMMETRIC, SYSTEM, SYSTEM_USER, TABLE, TABLESAMPLE, TABLE_NAME, TEMPORARY, THEN, TIES, TIME, TIMESTAMP, TIMESTAMPADD, TIMESTAMPDIFF, TIMEZONE_HOUR, TIMEZONE_MINUTE, TINYINT, TO, TOP_LEVEL_COUNT, TRAILING, TRANSACTION, TRANSACTIONS_ACTIVE, TRANSACTIONS_COMMITTED, TRANSACTIONS_ROLLED_BACK, TRANSFORM, TRANSFORMS, TRANSLATE, TRANSLATION, TREAT, TRIGGER, TRIGGER_CATALOG, TRIGGER_NAME, TRIGGER_SCHEMA, TRIM, TRUE, TYPE, UESCAPE, UNBOUNDED, UNCOMMITTED, UNDER, UNION, UNIQUE, UNKNOWN, UNNAMED, UNNEST, UPDATE, UPPER, UPSERT, USAGE, USER, USER_DEFINED_TYPE_CATALOG, USER_DEFINED_TYPE_CODE, USER_DEFINED_TYPE_NAME, USER_DEFINED_TYPE_SCHEMA, USING, VALUE, VALUES, VARBINARY, VARCHAR, VARYING, VAR_POP, VAR_SAMP, VERSION, VIEW, WEEK, WHEN, WHENEVER, WHERE, WIDTH_BUCKET, WINDOW, WITH, WITHIN, WITHOUT, WORK, WRAPPER, WRITE, XML, YEAR, ZONE.

Identifiers

Identifiers are the names of tables, columns and other metadata elements used in a SQL query.

Unquoted identifiers, such as emp, must start with a letter and can only contain letters, digits, and underscores. They are implicitly converted to upper case.

Quoted identifiers, such as "Employee Name", start and end with double quotes. They may contain virtually any character, including spaces and other punctuation. If you wish to include a double quote in an identifier, use another double quote to escape it, like this: "An employee called ""Fred"".".

In Calcite, matching identifiers to the name of the referenced object is case-sensitive. But remember that unquoted identifiers are implicitly converted to upper case before matching, and if the object it refers to was created using an unquoted identifier for its name, then its name will have been converted to upper case also.

Data types

Scalar types

Data type Description Range and examples
BOOLEAN Logical values Values: TRUE, FALSE, UNKNOWN
TINYINT 1 byte signed integer Range is -255 to 256
SMALLINT 2 byte signed integer Range is -32768 to 32767
INTEGER, INT 4 byte signed integer Range is -2147483648 to 2147483647
BIGINT 8 byte signed integer Range is -9223372036854775808 to 9223372036854775807
DECIMAL(p, s) Fixed point Example: 123.45 is a DECIMAL(5, 2) value.
NUMERIC Fixed point
REAL, FLOAT 4 byte floating point 6 decimal digits precision
DOUBLE 8 byte floating point 15 decimal digits precision
CHAR(n), CHARACTER(n) Fixed-width character string 'Hello', '' (empty string), _latin1'Hello', n'Hello', _UTF16'Hello', 'Hello' 'there' (literal split into multiple parts)
VARCHAR(n), CHARACTER VARYING(n) Variable-length character string As CHAR(n)
BINARY(n) Fixed-width binary string x'45F0AB', x'' (empty binary string), x'AB' 'CD' (multi-part binary string literal)
VARBINARY(n), BINARY VARYING(n) Variable-length binary string As BINARY(n)
DATE Date Example: DATE '1969-07-20'
TIME Time of day Example: TIME '20:17:40'
TIMESTAMP [ WITHOUT TIME ZONE ] Date and time Example: TIMESTAMP '1969-07-20 20:17:40'
TIMESTAMP WITH TIME ZONE Date and time with time zone Example: TIMESTAMP '1969-07-20 20:17:40 America/Los Angeles'
INTERVAL timeUnit [ TO timeUnit ] Date time interval Examples: INTERVAL '1:5' YEAR TO MONTH, INTERVAL '45' DAY
Anchored interval Date time interval Example: (DATE '1969-07-20', DATE '1972-08-29')

Where:

timeUnit:
  MILLENNIUM | CENTURY | DECADE | YEAR | QUARTER | MONTH | WEEK | DOY | DOW | DAY | HOUR | MINUTE | SECOND | EPOCH

Note:

  • DATE, TIME and TIMESTAMP have no time zone. There is not even an implicit time zone, such as UTC (as in Java) or the local time zone. It is left to the user or application to supply a time zone.

Non-scalar types

Type Description
ANY A value of an unknown type
ROW Row with 1 or more columns
MAP Collection of keys mapped to values
MULTISET Unordered collection that may contain duplicates
ARRAY Ordered, contiguous collection that may contain duplicates
CURSOR Cursor over the result of executing a query

Operators and functions

Operator precedence

The operator precedence and associativity, highest to lowest.

Operator Associativity
. left
left
+ - (unary plus, minus) right
* / left
+ - left
BETWEEN, IN, LIKE, SIMILAR -
< > = <= >= <> != left
IS NULL, IS FALSE, IS NOT TRUE etc. -
NOT right
AND left
OR left

Comparison operators

Operator syntax Description
value1 = value2 Equals
value1 <> value2 Not equal
value1 != value2 Not equal (only available at some conformance levels)
value1 > value2 Greater than
value1 >= value2 Greater than or equal
value1 < value2 Less than
value1 <= value2 Less than or equal
value IS NULL Whether value is null
value IS NOT NULL Whether value is not null
value1 IS DISTINCT FROM value2 Whether two values are not equal, treating null values as the same
value1 IS NOT DISTINCT FROM value2 Whether two values are equal, treating null values as the same
value1 BETWEEN value2 AND value3 Whether value1 is greater than or equal to value2 and less than or equal to value3
value1 NOT BETWEEN value2 AND value3 Whether value1 is less than value2 or greater than value3
string1 LIKE string2 [ ESCAPE string3 ] Whether string1 matches pattern string2
string1 NOT LIKE string2 [ ESCAPE string3 ] Whether string1 does not match pattern string2
string1 SIMILAR TO string2 [ ESCAPE string3 ] Whether string1 matches regular expression string2
string1 NOT SIMILAR TO string2 [ ESCAPE string3 ] Whether string1 does not match regular expression string2
value IN (value [, value]* ) Whether value is equal to a value in a list
value NOT IN (value [, value]* ) Whether value is not equal to every value in a list

Not supported yet on Storm SQL:

Operator syntax Description
value IN (sub-query) Whether value is equal to a row returned by sub-query
value NOT IN (sub-query) Whether value is not equal to every row returned by sub-query
EXISTS (sub-query) Whether sub-query returns at least one row

Storm SQL doesn't support sub-query yet, so above operators don't work properly. This will be addressed in near future.

Logical operators

Operator syntax Description
boolean1 OR boolean2 Whether boolean1 is TRUE or boolean2 is TRUE
boolean1 AND boolean2 Whether boolean1 and boolean2 are both TRUE
NOT boolean Whether boolean is not TRUE; returns UNKNOWN if boolean is UNKNOWN
boolean IS FALSE Whether boolean is FALSE; returns FALSE if boolean is UNKNOWN
boolean IS NOT FALSE Whether boolean is not FALSE; returns TRUE if boolean is UNKNOWN
boolean IS TRUE Whether boolean is TRUE; returns FALSE if boolean is UNKNOWN
boolean IS NOT TRUE Whether boolean is not TRUE; returns TRUE if boolean is UNKNOWN
boolean IS UNKNOWN Whether boolean is UNKNOWN
boolean IS NOT UNKNOWN Whether boolean is not UNKNOWN

Arithmetic operators and functions

Operator syntax Description
+ numeric Returns numeric
:- numeric Returns negative numeric
numeric1 + numeric2 Returns numeric1 plus numeric2
numeric1 - numeric2 Returns numeric1 minus numeric2
numeric1 * numeric2 Returns numeric1 multiplied by numeric2
numeric1 / numeric2 Returns numeric1 divided by numeric2
POWER(numeric1, numeric2) Returns numeric1 raised to the power of numeric2
ABS(numeric) Returns the absolute value of numeric
MOD(numeric, numeric) Returns the remainder (modulus) of numeric1 divided by numeric2. The result is negative only if numeric1 is negative
SQRT(numeric) Returns the square root of numeric
LN(numeric) Returns the natural logarithm (base e) of numeric
LOG10(numeric) Returns the base 10 logarithm of numeric
EXP(numeric) Returns e raised to the power of numeric
CEIL(numeric) Rounds numeric up, and returns the smallest number that is greater than or equal to numeric
FLOOR(numeric) Rounds numeric down, and returns the largest number that is less than or equal to numeric

Character string operators and functions

Operator syntax Description
string || string Concatenates two character strings.
CHAR_LENGTH(string) Returns the number of characters in a character string
CHARACTER_LENGTH(string) As CHAR_LENGTH(string)
UPPER(string) Returns a character string converted to upper case
LOWER(string) Returns a character string converted to lower case
POSITION(string1 IN string2) Returns the position of the first occurrence of string1 in string2
TRIM( { BOTH | LEADING | TRAILING } string1 FROM string2) Removes the longest string containing only the characters in string1 from the start/end/both ends of string1
OVERLAY(string1 PLACING string2 FROM integer [ FOR integer2 ]) Replaces a substring of string1 with string2
SUBSTRING(string FROM integer) Returns a substring of a character string starting at a given point.
SUBSTRING(string FROM integer FOR integer) Returns a substring of a character string starting at a given point with a given length.
INITCAP(string) Returns string with the first letter of each word converter to upper case and the rest to lower case. Words are sequences of alphanumeric characters separated by non-alphanumeric characters.

Not implemented:

  • SUBSTRING(string FROM regexp FOR regexp)

Binary string operators and functions

Operator syntax Description
binary || binary Concatenates two binary strings.
POSITION(binary1 IN binary2) Returns the position of the first occurrence of binary1 in binary2
OVERLAY(binary1 PLACING binary2 FROM integer [ FOR integer2 ]) Replaces a substring of binary1 with binary2

Known bugs:

Operator syntax Description
SUBSTRING(binary FROM integer) Returns a substring of binary starting at a given point
SUBSTRING(binary FROM integer FOR integer) Returns a substring of binary starting at a given point with a given length

Calcite 1.9.0 has bugs on binary SUBSTRING functions which throws exception while compiling SQL statements. This can be fixed to higher version of Calcite.

Date/time functions

Operator syntax Description
EXTRACT(timeUnit FROM datetime) Extracts and returns the value of a specified datetime field from a datetime value expression
FLOOR(datetime TO timeUnit) Rounds datetime down to timeUnit
CEIL(datetime TO timeUnit) Rounds datetime up to timeUnit

Not implemented:

  • EXTRACT(timeUnit FROM interval)
  • CEIL(interval)
  • FLOOR(interval)
  • datetime - datetime timeUnit [ TO timeUnit ]
  • interval OVERLAPS interval
  • + interval
  • - interval
  • interval + interval
  • interval - interval
  • interval / interval
  • datetime + interval
  • datetime - interval

Note on Storm SQL:

Operator syntax Description
LOCALTIME Returns the current date and time in the session time zone in a value of datatype TIME
LOCALTIME(precision) Returns the current date and time in the session time zone in a value of datatype TIME, with precision digits of precision
LOCALTIMESTAMP Returns the current date and time in the session time zone in a value of datatype TIMESTAMP
LOCALTIMESTAMP(precision) Returns the current date and time in the session time zone in a value of datatype TIMESTAMP, with precision digits of precision
CURRENT_TIME Returns the current time in the session time zone, in a value of datatype TIMESTAMP WITH TIME ZONE
CURRENT_DATE Returns the current date in the session time zone, in a value of datatype DATE
CURRENT_TIMESTAMP Returns the current date and time in the session time zone, in a value of datatype TIMESTAMP WITH TIME ZONE

SQL standard states that above operators should return the same value while evaluating query. Storm SQL converts each query to Trident topology and run, so technically current date / time should be fixed while evaluating SQL statement. Because of this limitation, current date / time will be fixed while creating Trident topology, and these operators should return the same value in the lifecycle of topology.

System functions

Not supported yet on Storm SQL:

Operator syntax Description
USER Equivalent to CURRENT_USER
CURRENT_USER User name of current execution context
SESSION_USER Session user name
SYSTEM_USER Returns the name of the current data store user as identified by the operating system
CURRENT_PATH Returns a character string representing the current lookup scope for references to user-defined routines and types
CURRENT_ROLE Returns the current active role

These operators are not making sense of Storm SQL's runtime, so it may be never supported unless we find out proper semantics.

Conditional functions and operators

Operator syntax Description
CASE value
WHEN value1 [, value11 ]* THEN result1
[ WHEN valueN [, valueN1 ]* THEN resultN ]*
[ ELSE resultZ ]
END
Simple case
CASE
WHEN condition1 THEN result1
[ WHEN conditionN THEN resultN ]*
[ ELSE resultZ ]
END
Searched case
NULLIF(value, value) Returns NULL if the values are the same.

For example, NULLIF(5, 5) returns NULL; NULLIF(5, 0) returns 5.
COALESCE(value, value [, value ]* ) Provides a value if the first value is null.

For example, COALESCE(NULL, 5) returns 5.

Type conversion

Operator syntax Description
CAST(value AS type) Converts a value to a given type.

Value constructors

Operator syntax Description
ROW (value [, value]* ) Creates a row from a list of values.
(value [, value]* ) Creates a row from a list of values.
map '[' key ']' Returns the element of a map with a particular key.
array '[' index ']' Returns the element at a particular location in an array.
ARRAY '[' value [, value ]* ']' Creates an array from a list of values.
MAP '[' key, value [, key, value ]* ']' Creates a map from a list of key-value pairs.

Collection functions

Operator syntax Description
ELEMENT(value) Returns the sole element of a array or multiset; null if the collection is empty; throws if it has more than one element.
CARDINALITY(value) Returns the number of elements in an array or multiset.

See also: UNNEST relational operator converts a collection to a relation.

JDBC function escape

Numeric

Operator syntax Description
{fn ABS(numeric)} Returns the absolute value of numeric
{fn EXP(numeric)} Returns e raised to the power of numeric
{fn LOG(numeric)} Returns the natural logarithm (base e) of numeric
{fn LOG10(numeric)} Returns the base-10 logarithm of numeric
{fn MOD(numeric1, numeric2)} Returns the remainder (modulus) of numeric1 divided by numeric2. The result is negative only if numeric1 is negative
{fn POWER(numeric1, numeric2)} Returns numeric1 raised to the power of numeric2

Not implemented:

  • {fn ACOS(numeric)} - Returns the arc cosine of numeric
  • {fn ASIN(numeric)} - Returns the arc sine of numeric
  • {fn ATAN(numeric)} - Returns the arc tangent of numeric
  • {fn ATAN2(numeric, numeric)}
  • {fn CEILING(numeric)} - Rounds numeric up, and returns the smallest number that is greater than or equal to numeric
  • {fn COS(numeric)} - Returns the cosine of numeric
  • {fn COT(numeric)}
  • {fn DEGREES(numeric)} - Converts numeric from radians to degrees
  • {fn FLOOR(numeric)} - Rounds numeric down, and returns the largest number that is less than or equal to numeric
  • {fn PI()} - Returns a value that is closer than any other value to pi
  • {fn RADIANS(numeric)} - Converts numeric from degrees to radians
  • {fn RAND(numeric)}
  • {fn ROUND(numeric, numeric)}
  • {fn SIGN(numeric)}
  • {fn SIN(numeric)} - Returns the sine of numeric
  • {fn SQRT(numeric)} - Returns the square root of numeric
  • {fn TAN(numeric)} - Returns the tangent of numeric
  • {fn TRUNCATE(numeric, numeric)}

String

Operator syntax Description
{fn CONCAT(character, character)} Returns the concatenation of character strings
{fn LOCATE(string1, string2)} Returns the position in string2 of the first occurrence of string1. Searches from the beginning of the second CharacterExpression, unless the startIndex parameter is specified.
{fn INSERT(string1, start, length, string2)} Inserts string2 into a slot in string1
{fn LCASE(string)} Returns a string in which all alphabetic characters in string have been converted to lower case
{fn LENGTH(string)} Returns the number of characters in a string
{fn SUBSTRING(string, offset, length)} Returns a character string that consists of length characters from string starting at the offset position
{fn UCASE(string)} Returns a string in which all alphabetic characters in string have been converted to upper case

Known bugs:

Operator syntax Description
{fn LOCATE(string1, string2 [, integer])} Returns the position in string2 of the first occurrence of string1. Searches from the beginning of string2, unless integer is specified.
{fn LTRIM(string)} Returns string with leading space characters removed
{fn RTRIM(string)} Returns string with trailing space characters removed

Calcite 1.9.0 throws exception on {fn LOCATE} with position parameter, {fn LTRIM} and {fn RTRIM} while compiling SQL statement. This can be fixed to higher version of Calcite.

Not implemented:

  • {fn ASCII(string)} - Convert a single-character string to the corresponding ASCII code, an integer between 0 and 255
  • {fn CHAR(string)}
  • {fn DIFFERENCE(string, string)}
  • {fn LEFT(string, integer)}
  • {fn REPEAT(string, integer)}
  • {fn REPLACE(string, string, string)}
  • {fn RIGHT(string, integer)}
  • {fn SOUNDEX(string)}
  • {fn SPACE(integer)}

Date/time

Operator syntax Description
{fn CURDATE()} Equivalent to CURRENT_DATE
{fn CURTIME()} Equivalent to LOCALTIME
{fn NOW()} Equivalent to LOCALTIMESTAMP
{fn QUARTER(date)} Equivalent to EXTRACT(QUARTER FROM date). Returns an integer between 1 and 4.
{fn TIMESTAMPADD(timeUnit, count, timestamp)} Adds an interval of count *timeUnit*s to a timestamp
{fn TIMESTAMPDIFF(timeUnit, timestamp1, timestamp2)} Subtracts timestamp1 from timestamp2 and returns the result in *timeUnit*s

Not implemented:

  • {fn DAYNAME(date)}
  • {fn DAYOFMONTH(date)}
  • {fn DAYOFWEEK(date)}
  • {fn DAYOFYEAR(date)}
  • {fn HOUR(time)}
  • {fn MINUTE(time)}
  • {fn MONTH(date)}
  • {fn MONTHNAME(date)}
  • {fn SECOND(time)}
  • {fn WEEK(date)}
  • {fn YEAR(date)}

System

Not implemented:

  • {fn DATABASE()}
  • {fn IFNULL(value, value)}
  • {fn USER(value, value)}
  • {fn CONVERT(value, type)}

Aggregate functions

Storm SQL doesn't support aggregation yet.

Window functions

Storm SQL doesn't support windowing yet.

Grouping functions

Storm SQL doesn't support grouping functions.

User-defined functions

Users can define user defined function (scalar) using CREATE FUNCTION statement. For example, the following statement defines MYPLUS function which uses org.apache.storm.sql.TestUtils$MyPlus class.

CREATE FUNCTION MYPLUS AS 'org.apache.storm.sql.TestUtils$MyPlus'

Storm SQL determines whether the function as scalar or aggregate by checking which methods are defined. If the class defines evaluate method, Storm SQL treats the function as scalar.

Example of class for scalar function is here:

  public class MyPlus {
    public static Integer evaluate(Integer x, Integer y) {
      return x + y;
    }
  }

Please note that users should use --jars or --artifacts while running Storm SQL runner to make sure UDFs are available in classpath.

External Data Sources

Specifying External Data Sources

In StormSQL data is represented by external tables. Users can specify data sources using the CREATE EXTERNAL TABLE statement. The syntax of CREATE EXTERNAL TABLE closely follows the one defined in Hive Data Definition Language:

CREATE EXTERNAL TABLE table_name field_list
    [ STORED AS
      INPUTFORMAT input_format_classname
      OUTPUTFORMAT output_format_classname
    ]
    LOCATION location
    [ TBLPROPERTIES tbl_properties ]
    [ AS select_stmt ]

Default input format and output format are JSON. We will introduce supported formats from further section.

For example, the following statement specifies a Kafka spout and sink:

CREATE EXTERNAL TABLE FOO (ID INT PRIMARY KEY) LOCATION 'kafka://localhost:2181/brokers?topic=test' TBLPROPERTIES '{"producer":{"bootstrap.servers":"localhost:9092","acks":"1","key.serializer":"org.apache.org.apache.storm.kafka.IntSerializer","value.serializer":"org.apache.org.apache.storm.kafka.ByteBufferSerializer"}}'

Please note that users should use --jars or --artifacts while running Storm SQL runner to make sure UDFs are available in classpath.

Plugging in External Data Sources

Users plug in external data sources through implementing the ISqlTridentDataSource interface and registers them using the mechanisms of Java's service loader. The external data source will be chosen based on the scheme of the URI of the tables. Please refer to the implementation of storm-sql-kafka for more details.

Supported Formats

Format Input format class Output format class Requires properties
JSON org.apache.storm.sql.runtime.serde.json.JsonScheme org.apache.storm.sql.runtime.serde.json.JsonSerializer No
Avro org.apache.storm.sql.runtime.serde.avro.AvroScheme org.apache.storm.sql.runtime.serde.avro.AvroSerializer Yes
CSV org.apache.storm.sql.runtime.serde.csv.CsvScheme org.apache.storm.sql.runtime.serde.csv.CsvSerializer No
TSV org.apache.storm.sql.runtime.serde.tsv.TsvScheme org.apache.storm.sql.runtime.serde.tsv.TsvSerializer No

Avro

Avro requires users to describe the schema of record (both input and output). Schema should be described on TBLPROPERTIES. Input format needs to be described to input.avro.schema, and output format needs to be described to output.avro.schema. Schema string should be an escaped JSON so that TBLPROPERTIES is valid JSON.

Example Schema description:

"input.avro.schema": "{\"type\": \"record\", \"name\": \"large_orders\", \"fields\" : [ {\"name\": \"ID\", \"type\": \"int\"}, {\"name\": \"TOTAL\", \"type\": \"int\"} ]}"

"output.avro.schema": "{\"type\": \"record\", \"name\": \"large_orders\", \"fields\" : [ {\"name\": \"ID\", \"type\": \"int\"}, {\"name\": \"TOTAL\", \"type\": \"int\"} ]}"

CSV

It uses Standard RFC4180 CSV Parser and doesn't need any other properties.

TSV

By default TSV uses \t as delimiter, but users can set another delimiter by setting input.tsv.delimiter and/or output.tsv.delimiter. Please note that it supports only one letter for delimiter.

Supported Data Sources

Data Source Artifact Name Location prefix Support Input data source Support Output data source Requires properties
Socket socket://host:port Yes Yes No
Kafka org.apache.storm:storm-sql-kafka kafka://zkhost:port/broker_path?topic=topic Yes Yes Yes
Redis org.apache.storm:storm-sql-redis redis://:[password]@host:port/[dbIdx] No Yes Yes
MongoDB org.apache.stormg:storm-sql-mongodb mongodb://[username:password@]host1[:port1][,host2[:port2],...[,hostN[:portN]]][/[database][?options]] No Yes Yes
HDFS org.apache.storm:storm-sql-hdfs hdfs://host:port/path-to-file No Yes Yes

Socket

Socket data source is a built-in feature so users don't need to add any artifacts to --artifacts options.

Please note that Socket data source is only for testing: it doesn't guarantee exactly-once and at-least-once.

TIP: netcat is a convenient tool for Socket: users can use netcat to connect Socket data source for either or both input and output purposes.

Kafka

Kafka data source requires below properties only when its used for output data source:

  • producer: Specify Kafka Producer configuration - Please refer Kafka producer configs for details.
    • bootstrap.servers must be described in producer

Please note that storm-sql-kafka requires users to provide storm-kafka, and storm-kafka requires users to provide kafka and kafka-clients. You can use below as working reference for --artifacts option, and change dependencies version, and see it works:

org.apache.storm:storm-sql-kafka:2.0.0-SNAPSHOT,org.apache.storm:storm-kafka:2.0.0-SNAPSHOT,org.apache.kafka:kafka_2.10:0.8.2.2^org.slf4j:slf4j-log4j12,org.apache.kafka:kafka-clients:0.8.2.2

Redis

Redis data source requires below properties to be set:

  • data.type: data type to be used for storing - only "STRING" and "HASH" are supported
  • data.additional.key: key if data type needs both key and field (field will be used as field)
  • redis.timeout: timeout in milliseconds (ex. "3000")
  • use.redis.cluster: "true" if data source is Redis Cluster env., "false" otherwise.

Please note that storm-sql-redis requires users to provide storm-redis. You can use below as working reference for --artifacts option, and change dependencies version if really needed:

org.apache.storm:storm-sql-redis:2.0.0-SNAPSHOT,org.apache.storm:storm-redis:2.0.0-SNAPSHOT

MongoDB

MongoDB data source requires below properties to be set:

{"collection.name": "storm_sql_mongo", "trident.ser.field": "serfield"}

  • trident.ser.field: field to store - record will be serialized and stored as BSON in this field
  • collection.name: Collection name

Please note that storm-sql-mongodb requires users to provide storm-mongodb. You can use below as working reference for --artifacts option, and change dependencies version if really needed:

org.apache.storm:storm-sql-mongodb:2.0.0-SNAPSHOT,org.apache.storm:storm-mongodb:2.0.0-SNAPSHOT

Storing record with preserving fields are not supported for now.

HDFS

HDFS data source requires below properties to be set:

  • hdfs.file.path: HDFS file path
  • hdfs.file.name: HDFS file name - please refer to SimpleFileNameFormat
  • hdfs.rotation.size.kb: HDFS FileSizeRotationPolicy in KB
  • hdfs.rotation.time.seconds: HDFS TimedRotationPolicy in seconds

Please note that hdfs.rotation.size.kb and hdfs.rotation.time.seconds only one can be used for hdfs rotation.

And note that storm-sql-hdfs requires users to provide storm-hdfs. You can use below as working reference for --artifacts option, and change dependencies version if really needed:

org.apache.storm:storm-sql-hdfs:2.0.0-SNAPSHOT,org.apache.storm:storm-hdfs:2.0.0-SNAPSHOT

Also, hdfs configuration files should be provided. You can put the core-site.xml and hdfs-site.xml into the conf directory which is in Storm installation directory.