org.apache.calcite.sql.dialect

Class MysqlSqlDialect

java.lang.Object

org.apache.calcite.sql.SqlDialect

org.apache.calcite.sql.dialect.MysqlSqlDialect

public class MysqlSqlDialect
extends SqlDialect

A SqlDialect implementation for the MySQL 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 SqlFunction	ISNULL_FUNCTION MySQL specific function.

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

CALCITE, DUMMY, EMPTY_CONTEXT, LOGGER, nullCollation

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
SqlNode	emulateNullDirection(SqlNode node, boolean nullsFirst, boolean desc) Returns the SqlNode for emulating the null direction for the given field or null if no emulation needs to be done.
SqlDialect.CalendarPolicy	getCalendarPolicy()
SqlNode	getCastSpec(RelDataType type)
SqlNode	rewriteSingleValueExpr(SqlNode aggCall) Rewrite SINGLE_VALUE into expression based on database variants E.g.
boolean	supportsAggregateFunction(SqlKind kind)
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	supportsNestedAggregations() Returns whether the dialect supports nested aggregations, for instance SELECT SUM(SUM(1)) .
void	unparseCall(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec)
private void	unparseFloor(SqlWriter writer, SqlCall call) Unparses datetime floor for MySQL.
void	unparseOffsetFetch(SqlWriter writer, SqlNode offset, SqlNode fetch) Converts an offset and fetch into SQL.

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

allowsAs, create, defaultNullDirection, emptyContext, emulateNullDirectionWithIsNull, getDatabaseProduct, getNullCollation, getProduct, hasImplicitTableAlias, identifierNeedsToBeQuoted, quoteIdentifier, quoteIdentifier, quoteIdentifier, quoteStringLiteral, quoteStringLiteralUnicode, quoteTimestampLiteral, requiresAliasForFromItems, supportsAliasedValues, supportsFunction, supportsOffsetFetch, unparseDateTimeLiteral, unparseFetchUsingAnsi, unparseFetchUsingLimit, unquoteStringLiteral

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT

public static final SqlDialect DEFAULT

ISNULL_FUNCTION

public static final SqlFunction ISNULL_FUNCTION

MySQL specific function.

Constructor Detail

MysqlSqlDialect

public MysqlSqlDialect(SqlDialect.Context context)

Creates a MysqlSqlDialect.

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

unparseOffsetFetch

public void unparseOffsetFetch(SqlWriter writer,
                               SqlNode offset,
                               SqlNode fetch)

Description copied from class: SqlDialect

Converts an offset and fetch into SQL.

At least one of offset and fetch must be provided.

Common options:

• OFFSET offset ROWS FETCH NEXT fetch ROWS ONLY (ANSI standard SQL, Oracle, PostgreSQL, and the default)
• LIMIT fetch OFFSET offset (Apache Hive, MySQL, Redshift)

Overrides:

unparseOffsetFetch in class SqlDialect

Parameters:

writer - Writer

offset - Number of rows to skip before emitting, or null

fetch - Number of rows to fetch, or null

See Also:

SqlDialect.unparseFetchUsingAnsi(SqlWriter, SqlNode, SqlNode), SqlDialect.unparseFetchUsingLimit(SqlWriter, SqlNode, SqlNode)

emulateNullDirection

public SqlNode emulateNullDirection(SqlNode node,
                                    boolean nullsFirst,
                                    boolean desc)

Description copied from class: SqlDialect

Returns the SqlNode for emulating the null direction for the given field or null if no emulation needs to be done.

Overrides:

emulateNullDirection in class SqlDialect

Parameters:

node - The SqlNode representing the expression

nullsFirst - Whether nulls should come first

desc - Whether the sort direction is RelFieldCollation.Direction.DESCENDING or RelFieldCollation.Direction.STRICTLY_DESCENDING

Returns:

A SqlNode for null direction emulation or null if not required

supportsAggregateFunction

public boolean supportsAggregateFunction(SqlKind kind)

Overrides:

supportsAggregateFunction 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

getCalendarPolicy

public SqlDialect.CalendarPolicy getCalendarPolicy()

Overrides:

getCalendarPolicy in class SqlDialect

getCastSpec

public SqlNode getCastSpec(RelDataType type)

Overrides:

getCastSpec in class SqlDialect

rewriteSingleValueExpr

public SqlNode rewriteSingleValueExpr(SqlNode aggCall)

Description copied from class: SqlDialect

Rewrite SINGLE_VALUE into expression based on database variants E.g. HSQLDB, MYSQL, ORACLE, etc

Overrides:

rewriteSingleValueExpr in class SqlDialect

unparseCall

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

Overrides:

unparseCall in class SqlDialect

unparseFloor

private void unparseFloor(SqlWriter writer,
                          SqlCall call)

Unparses datetime floor for MySQL. There is no TRUNC function, so simulate this using calls to DATE_FORMAT.

Parameters:

writer - Writer

call - Call