Package org.apache.calcite.sql.dialect

Class ClickHouseSqlDialect

java.lang.Object

org.apache.calcite.sql.SqlDialect

org.apache.calcite.sql.dialect.ClickHouseSqlDialect

public class ClickHouseSqlDialect
extends SqlDialect

A SqlDialect implementation for the ClickHouse 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	Description
static final SqlDialect	DEFAULT
static final SqlDialect.Context	DEFAULT_CONTEXT
static final RelDataTypeSystem	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	Description
ClickHouseSqlDialect(SqlDialect.Context context)	Creates a ClickHouseSqlDialect.

Method Summary

Modifier and Type	Method	Description
SqlDialect.CalendarPolicy	getCalendarPolicy()
@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.
RexNode	prepareUnparse(RexNode arg)	Converts RexNode expression to RexNode expression before unparse.
boolean	supportsAliasedValues()	Returns whether the dialect supports VALUES in a sub-query with and an "AS t(column, ...)" values to define column names.
boolean	supportsApproxCountDistinct()	Returns whether this dialect supports APPROX_COUNT_DISTINCT functions.
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)) .
boolean	supportsWindowFunctions()	Returns whether this dialect supports window functions (OVER clause).
void	unparseBoolLiteral(SqlWriter writer, SqlLiteral literal, int leftPrec, int rightPrec)
void	unparseCall(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec)
void	unparseDateTimeLiteral(SqlWriter writer, SqlAbstractDateTimeLiteral literal, int leftPrec, int rightPrec)
void	unparseOffsetFetch(SqlWriter writer, @Nullable SqlNode offset, @Nullable SqlNode fetch)	Converts an offset and fetch into SQL.

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

allowsAs, configureParser, configureParser, containsNonAscii, create, defaultNullDirection, emulateJoinTypeForCrossJoin, emulateNullDirection, emulateNullDirectionWithIsNull, getConformance, getDatabaseProduct, getFormatModel, getNullCollation, getProduct, getQuotedCasing, getQuoting, getSingleRowTableName, getTypeSystem, getUnquotedCasing, hasImplicitTableAlias, identifierNeedsQuote, isCaseSensitive, quoteIdentifier, quoteIdentifier, quoteIdentifier, quoteStringLiteral, quoteStringLiteral, quoteStringLiteralUnicode, quoteTimestampLiteral, requiresAliasForFromItems, rewriteMaxMin, rewriteMaxMinExpr, rewriteSingleValueExpr, supportBooleanCaseWhen, supportGenerateSelectStar, supportsAggregateFunction, supportsAggregateFunctionFilter, supportsDataType, supportsFunction, supportsGroupByLiteral, supportsGroupByWithCube, supportsGroupByWithRollup, supportsImplicitTypeCoercion, supportsJoinType, supportsOffsetFetch, supportsOrderByLiteral, supportsTimestampPrecision, unparseFetchUsingAnsi, unparseFetchUsingLimit, unparseLimit, unparseNumericLiteral, unparseOffset, unparseSqlDatetimeArithmetic, unparseSqlIntervalLiteral, unparseSqlIntervalQualifier, unparseSqlSetOption, unparseTableScanHints, unparseTopN, unquoteStringLiteral

Methods inherited from class java.lang.Object

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

Field Details

TYPE_SYSTEM

public static final RelDataTypeSystem TYPE_SYSTEM

DEFAULT_CONTEXT

public static final SqlDialect.Context DEFAULT_CONTEXT

DEFAULT

public static final SqlDialect DEFAULT

Constructor Details

ClickHouseSqlDialect

public ClickHouseSqlDialect(SqlDialect.Context context)

Creates a ClickHouseSqlDialect.

Method Details

supportsApproxCountDistinct

public boolean supportsApproxCountDistinct()

Description copied from class: SqlDialect

Returns whether this dialect supports APPROX_COUNT_DISTINCT functions.

Overrides:

supportsApproxCountDistinct in class SqlDialect

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

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

supportsWindowFunctions

public boolean supportsWindowFunctions()

Description copied from class: SqlDialect

Returns whether this dialect supports window functions (OVER clause).

Overrides:

supportsWindowFunctions in class SqlDialect

supportsAliasedValues

public boolean supportsAliasedValues()

Description copied from class: SqlDialect

Returns whether the dialect supports VALUES in a sub-query with and an "AS t(column, ...)" values to define column names.

Currently, only Oracle does not. For this, we generate "SELECT v0 AS c0, v1 AS c1 ... UNION ALL ...". We may need to refactor this method when we support VALUES for other dialects.

Overrides:

supportsAliasedValues in class SqlDialect

getCalendarPolicy

public SqlDialect.CalendarPolicy getCalendarPolicy()

Overrides:

getCalendarPolicy in class SqlDialect

prepareUnparse

public RexNode prepareUnparse(RexNode arg)

Description copied from class: SqlDialect

Converts RexNode expression to RexNode expression before unparse.

Overrides:

prepareUnparse 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

unparseDateTimeLiteral

public void unparseDateTimeLiteral(SqlWriter writer,
 SqlAbstractDateTimeLiteral literal,
 int leftPrec,
 int rightPrec)

Overrides:

unparseDateTimeLiteral in class SqlDialect

unparseBoolLiteral

public void unparseBoolLiteral(SqlWriter writer,
 SqlLiteral literal,
 int leftPrec,
 int rightPrec)

Overrides:

unparseBoolLiteral in class SqlDialect

unparseOffsetFetch

public void unparseOffsetFetch(SqlWriter writer,
 @Nullable SqlNode offset,
 @Nullable 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)

unparseCall

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

Overrides:

unparseCall in class SqlDialect