Help Center/ Data Lake Insight/ SQL Syntax Reference (Kuala Lumpur Region)/ Flink SQL Syntax/ SQL Syntax Constraints and Definitions
Updated on 2023-03-06 GMT+08:00
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SQL Syntax Constraints and Definitions

Syntax Constraints

  • Currently, Flink SQL only supports the following operations: SELECT, FROM, WHERE, UNION, aggregation, window, JOIN between stream and table data, and JOIN between streams.
  • Data cannot be inserted into the source stream.
  • The sink stream cannot be used to perform query operations.

Data Types Supported by Syntax

  • Basic data types: VARCHAR, STRING, BOOLEAN, TINYINT, SMALLINT, INTEGER/INT, BIGINT, REAL/FLOAT, DOUBLE, DECIMAL, DATE, TIME, and TIMESTAMP
  • Array: Square brackets ([]) are used to quote fields. The following is an example: 
    1
    		 
    insert into temp select CARDINALITY(ARRAY[1,2,3]) FROM OrderA;

Syntax Definition

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INSERT INTO stream_name query;
query:
  values
  | {
      select
      | selectWithoutFrom
      | query UNION [ ALL ] query
    }

orderItem:
  expression [ ASC | DESC ]

select:
  SELECT 
  { * | projectItem [, projectItem ]* }
  FROM tableExpression [ JOIN tableExpression ]
  [ WHERE booleanExpression ]
  [ GROUP BY { groupItem [, groupItem ]* } ]
  [ HAVING booleanExpression ]

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

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

tableExpression:
  tableReference 

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

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

values:
  VALUES expression [, expression ]*

groupItem:
  expression
  | '(' ')'
  | '(' expression [, expression ]* ')'
  | CUBE '(' expression [, expression ]* ')'
  | ROLLUP '(' expression [, expression ]* ')'
  | GROUPING SETS '(' groupItem [, groupItem ]* ')'
Parent topic: Flink SQL Syntax