org.apache.calcite.sql.dialect

Class PostgresqlSqlDialect

java.lang.Object

org.apache.calcite.sql.SqlDialect

org.apache.calcite.sql.dialect.PostgresqlSqlDialect

public class PostgresqlSqlDialect
extends SqlDialect

A SqlDialect implementation for the PostgreSQL database.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.calcite.sql.SqlDialect

SqlDialect.CalendarPolicy, SqlDialect.Context, SqlDialect.DatabaseProduct, SqlDialect.FakeUtil

Field Summary

Fields

Modifier and Type	Field and Description
static SqlDialect	DEFAULT
static SqlDialect.Context	DEFAULT_CONTEXT
static RelDataTypeSystem	POSTGRESQL_TYPE_SYSTEM PostgreSQL type system.

Fields inherited from class org.apache.calcite.sql.SqlDialect

BUILT_IN_OPERATORS_LIST, EMPTY_CONTEXT, identifierEndQuoteString, identifierEscapedQuote, identifierQuoteString, literalEndQuoteString, literalEscapedQuote, literalQuoteString, LOGGER, nullCollation

Constructor Summary

Constructors

Constructor and Description
PostgresqlSqlDialect(SqlDialect.Context context) Creates a PostgresqlSqlDialect.

Method Summary

Modifier and Type	Method and Description
@Nullable SqlNode	getCastSpec(RelDataType type) Returns SqlNode for type in "cast(column as type)", which might be different between databases by type name, precision etc.
boolean	requiresAliasForFromItems() Whether a sub-query in the FROM clause must have an alias.
boolean	supportsCharSet() Returns whether the dialect supports character set names as part of a data type, for instance VARCHAR(30) CHARACTER SET `ISO-8859-1`.
boolean	supportsFunction(SqlOperator operator, RelDataType type, List<RelDataType> paramTypes) Returns whether this dialect supports a given function or operator.
boolean	supportsGroupByLiteral() Returns whether the dialect supports GROUP BY literals.
boolean	supportsNestedAggregations() Returns whether the dialect supports nested aggregations, for instance SELECT SUM(SUM(1)) .
void	unparseCall(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec)

Methods inherited from class org.apache.calcite.sql.SqlDialect

allowsAs, configureParser, configureParser, containsNonAscii, create, defaultNullDirection, emulateJoinTypeForCrossJoin, emulateNullDirection, emulateNullDirectionWithIsNull, getCalendarPolicy, getConformance, getDatabaseProduct, getNullCollation, getProduct, getQuotedCasing, getQuoting, getSingleRowTableName, getTypeSystem, getUnquotedCasing, hasImplicitTableAlias, identifierNeedsQuote, isCaseSensitive, quoteIdentifier, quoteIdentifier, quoteIdentifier, quoteStringLiteral, quoteStringLiteral, quoteStringLiteralUnicode, quoteTimestampLiteral, rewriteSingleValueExpr, supportsAggregateFunction, supportsAggregateFunctionFilter, supportsAliasedValues, supportsApproxCountDistinct, supportsDataType, supportsGroupByWithCube, supportsGroupByWithRollup, supportsImplicitTypeCoercion, supportsJoinType, supportsOffsetFetch, supportsWindowFunctions, unparseDateTimeLiteral, unparseFetchUsingAnsi, unparseFetchUsingLimit, unparseLimit, unparseOffset, unparseOffsetFetch, unparseSqlDatetimeArithmetic, unparseSqlIntervalLiteral, unparseSqlIntervalQualifier, unparseTableScanHints, unparseTopN, unquoteStringLiteral

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

POSTGRESQL_TYPE_SYSTEM

public static final RelDataTypeSystem POSTGRESQL_TYPE_SYSTEM

PostgreSQL type system.

DEFAULT_CONTEXT

public static final SqlDialect.Context DEFAULT_CONTEXT

DEFAULT

public static final SqlDialect DEFAULT

Constructor Detail

PostgresqlSqlDialect

public PostgresqlSqlDialect(SqlDialect.Context context)

Creates a PostgresqlSqlDialect.

Method Detail

supportsCharSet

public boolean supportsCharSet()

Description copied from class: SqlDialect

Returns whether the dialect supports character set names as part of a data type, for instance VARCHAR(30) CHARACTER SET `ISO-8859-1`.

Overrides:

supportsCharSet in class SqlDialect

getCastSpec

public @Nullable SqlNode getCastSpec(RelDataType type)

Description copied from class: SqlDialect

Returns SqlNode for type in "cast(column as type)", which might be different between databases by type name, precision etc.

If this method returns null, the cast will be omitted. In the default implementation, this is the case for the NULL type, and therefore CAST(NULL AS <nulltype>) is rendered as NULL.

Overrides:

getCastSpec in class SqlDialect

supportsFunction

public boolean supportsFunction(SqlOperator operator,
                                RelDataType type,
                                List<RelDataType> paramTypes)

Description copied from class: SqlDialect

Returns whether this dialect supports a given function or operator. It only applies to built-in scalar functions and operators, since user-defined functions and procedures should be read by JdbcSchema.

Overrides:

supportsFunction in class SqlDialect

requiresAliasForFromItems

public boolean requiresAliasForFromItems()

Description copied from class: SqlDialect

Whether a sub-query in the FROM clause must have an alias.

For example, in PostgreSQL, this query is legal:

SELECT * FROM (SELECT * FROM Emp) As e

but remove the alias e and it is not:

SELECT * FROM (SELECT * FROM Emp)

In Oracle, both queries are legal.

Overrides:

requiresAliasForFromItems in class SqlDialect

supportsNestedAggregations

public boolean supportsNestedAggregations()

Description copied from class: SqlDialect

Returns whether the dialect supports nested aggregations, for instance SELECT SUM(SUM(1)) .

Overrides:

supportsNestedAggregations in class SqlDialect

unparseCall

public void unparseCall(SqlWriter writer,
                        SqlCall call,
                        int leftPrec,
                        int rightPrec)

Overrides:

unparseCall in class SqlDialect

supportsGroupByLiteral

public boolean supportsGroupByLiteral()

Description copied from class: SqlDialect

Returns whether the dialect supports GROUP BY literals.

For instance, in SqlDialect.DatabaseProduct.REDSHIFT, the following queries are illegal.

 select avg(salary)
 from emp
 group by true
 

 select avg(salary)
 from emp
 group by 'a', DATE '2022-01-01'
 

Overrides:

supportsGroupByLiteral in class SqlDialect