Package org.apache.calcite.sql.babel.postgres

Class SqlDiscard

java.lang.Object

org.apache.calcite.sql.SqlNode

org.apache.calcite.sql.SqlCall

org.apache.calcite.sql.babel.postgres.SqlDiscard

All Implemented Interfaces:

Cloneable

public class SqlDiscard
extends SqlCall

Parse tree node representing a DISCARD clause.

See Also:

• DISCARD specification

Field Summary

Fields

Modifier and Type	Field	Description
static final SqlBasicOperator	OPERATOR

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

EMPTY_ARRAY, pos

Constructor Summary

Constructors

Constructor	Description
SqlDiscard(SqlParserPos pos, SqlIdentifier subcommand)

Method Summary

Modifier and Type	Method	Description
List<SqlNode>	getOperandList()	Returns the list of operands.
SqlOperator	getOperator()
void	unparse(SqlWriter writer, int leftPrec, int rightPrec)	Writes a SQL representation of this node to a writer.

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

accept, clone, equalsDeep, findValidOptions, getCallSignature, getFunctionQuantifier, getKind, getMonotonicity, isCountStar, isExpanded, operand, operandCount, setOperand, validate

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

clone, clone, cloneArray, equalDeep, equalDeep, equalsDeep, getParserPosition, isA, toList, toList, toSqlString, toSqlString, toSqlString, toString, unparseWithParentheses, validateExpr

Methods inherited from class java.lang.Object

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

Field Details

OPERATOR

public static final SqlBasicOperator OPERATOR

Constructor Details

SqlDiscard

public SqlDiscard(SqlParserPos pos,
 SqlIdentifier subcommand)

Method Details

getOperator

public SqlOperator getOperator()

Specified by:

getOperator in class SqlCall

getOperandList

public List<SqlNode> getOperandList()

Description copied from class: SqlCall

Returns the list of operands. The set and order of operands is call-specific.

Note: the proper type would be List<@Nullable SqlNode>, however, it would trigger too many changes to the current codebase.

Specified by:

getOperandList in class SqlCall

Returns:

the list of call operands, never null, the operands can be null

unparse

public void unparse(SqlWriter writer,
 int leftPrec,
 int rightPrec)

Description copied from class: SqlNode

Writes a SQL representation of this node to a writer.

The leftPrec and rightPrec parameters give us enough context to decide whether we need to enclose the expression in parentheses. For example, we need parentheses around "2 + 3" if preceded by "5 *". This is because the precedence of the "*" operator is greater than the precedence of the "+" operator.

The algorithm handles left- and right-associative operators by giving them slightly different left- and right-precedence.

If SqlWriter.isAlwaysUseParentheses() is true, we use parentheses even when they are not required by the precedence rules.

For the details of this algorithm, see SqlCall.unparse(org.apache.calcite.sql.SqlWriter, int, int).

Overrides:

unparse in class SqlCall

Parameters:

writer - Target writer

leftPrec - The precedence of the SqlNode immediately preceding this node in a depth-first scan of the parse tree

rightPrec - The precedence of the SqlNode immediately