Package org.h2.expression
Class Rownum
java.lang.Object
org.h2.expression.Expression
org.h2.expression.Operation0
org.h2.expression.Rownum
Represents the ROWNUM function.
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Field Summary
FieldsFields inherited from class org.h2.expression.Expression
AUTO_PARENTHESES, MAP_IN_AGGREGATE, MAP_IN_WINDOW, MAP_INITIAL, WITH_PARENTHESES, WITHOUT_PARENTHESES
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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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
getCost()
Estimate the cost to process the expression.getType()
Returns the data type.getUnenclosedSQL
(StringBuilder builder, int sqlFlags) Get the SQL statement of this expression.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.optimize
(SessionLocal session) Try to optimize the expression.Methods inherited from class org.h2.expression.Operation0
mapColumns, setEvaluatable, updateAggregate
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
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Methods inherited from interface org.h2.util.HasSQL
getTraceSQL
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Field Details
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prepared
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singleRow
private boolean singleRow
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Constructor Details
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Rownum
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Method Details
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getValue
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
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
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
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
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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