SQL Syntax Constraints and Definitions

Updated on 2023-11-03 GMT+08:00

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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

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 ]* ')'