Package org.h2.expression
Class Rownum
- java.lang.Object
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- org.h2.expression.Expression
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- org.h2.expression.Operation0
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- org.h2.expression.Rownum
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public final class Rownum extends Operation0
Represents the ROWNUM function.
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Field Summary
Fields Modifier and Type Field Description private Prepared
prepared
private boolean
singleRow
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Fields inherited from class org.h2.expression.Expression
AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES
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Fields inherited from interface org.h2.util.HasSQL
ADD_PLAN_INFORMATION, DEFAULT_SQL_FLAGS, NO_CASTS, QUOTE_ONLY_WHEN_REQUIRED, REPLACE_LOBS_FOR_TRACE, TRACE_SQL_FLAGS
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
getCost()
Estimate the cost to process the expression.TypeInfo
getType()
Returns the data type.java.lang.StringBuilder
getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags)
Get the SQL statement of this expression.Value
getValue(SessionLocal session)
Return the resulting value for the current row.boolean
isEverything(ExpressionVisitor visitor)
Check if this expression and all sub-expressions can fulfill a criteria.Expression
optimize(SessionLocal session)
Try to optimize the expression.-
Methods inherited from class org.h2.expression.Operation0
mapColumns, setEvaluatable, updateAggregate
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Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getSubexpression, getSubexpressionCount, getTableAlias, getTableName, getWhenSQL, getWhenValue, isConstant, isIdentity, isNullConstant, isValueSet, isWhenConditionOperand, needParentheses, optimizeCondition, toString, writeExpressions, writeExpressions
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.h2.util.HasSQL
getTraceSQL
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Field Detail
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prepared
private final Prepared prepared
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singleRow
private boolean singleRow
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Constructor Detail
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Rownum
public Rownum(Prepared prepared)
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Method Detail
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getValue
public Value getValue(SessionLocal session)
Description copied from class:Expression
Return the resulting value for the current row.- Specified by:
getValue
in classExpression
- Parameters:
session
- the session- Returns:
- the result
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getType
public TypeInfo getType()
Description copied from class:Expression
Returns the data type. The data type may be unknown before the optimization phase.- Specified by:
getType
in interfaceTyped
- Specified by:
getType
in classExpression
- Returns:
- the data type
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getUnenclosedSQL
public java.lang.StringBuilder getUnenclosedSQL(java.lang.StringBuilder builder, int sqlFlags)
Description copied from class:Expression
Get the SQL statement of this expression. This may not always be the original SQL statement, especially after optimization. Enclosing '(' and ')' are never appended.- Specified by:
getUnenclosedSQL
in classExpression
- Parameters:
builder
- string buildersqlFlags
- formatting flags- Returns:
- the specified string builder
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optimize
public Expression optimize(SessionLocal session)
Description copied from class:Expression
Try to optimize the expression.- Overrides:
optimize
in classOperation0
- Parameters:
session
- the session- Returns:
- the optimized expression
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isEverything
public boolean isEverything(ExpressionVisitor visitor)
Description copied from class:Expression
Check if this expression and all sub-expressions can fulfill a criteria. If any part returns false, the result is false.- Specified by:
isEverything
in classExpression
- Parameters:
visitor
- the visitor- Returns:
- if the criteria can be fulfilled
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getCost
public int getCost()
Description copied from class:Expression
Estimate the cost to process the expression. Used when optimizing the query, to calculate the query plan with the lowest estimated cost.- Specified by:
getCost
in classExpression
- Returns:
- the estimated cost
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