Package org.h2.expression
Class ExpressionList
java.lang.Object
org.h2.expression.Expression
org.h2.expression.ExpressionList
A list of expressions, as in (ID, NAME).
The result of this expression is a row or an array.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate final boolean
private final Expression[]
private TypeInfo
Fields 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.getSubexpression
(int index) Returns subexpression with specified index.int
Returns count of subexpressions.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.(package private) void
boolean
isArray()
boolean
Check if this expression will always return the same value.boolean
isEverything
(ExpressionVisitor visitor) Check if this expression and all sub-expressions can fulfill a criteria.void
mapColumns
(ColumnResolver resolver, int level, int state) Map the columns of the resolver to expression columns.optimize
(SessionLocal session) Try to optimize the expression.void
setEvaluatable
(TableFilter tableFilter, boolean b) Tell the expression columns whether the table filter can return values now.void
updateAggregate
(SessionLocal session, int stage) Update an aggregate value.Methods inherited from class org.h2.expression.Expression
addFilterConditions, createIndexConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNotIfPossible, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, getWhenSQL, getWhenValue, 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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list
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isArray
private final boolean isArray -
type
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Constructor Details
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ExpressionList
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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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mapColumns
Description copied from class:Expression
Map the columns of the resolver to expression columns.- Specified by:
mapColumns
in classExpression
- Parameters:
resolver
- the column resolverlevel
- the subquery nesting levelstate
- current state for nesting checks, initial value isExpression.MAP_INITIAL
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optimize
Description copied from class:Expression
Try to optimize the expression.- Specified by:
optimize
in classExpression
- Parameters:
session
- the session- Returns:
- the optimized expression
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initializeType
void initializeType() -
setEvaluatable
Description copied from class:Expression
Tell the expression columns whether the table filter can return values now. This is used when optimizing the query.- Specified by:
setEvaluatable
in classExpression
- Parameters:
tableFilter
- the table filterb
- true if the table filter can return value
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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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updateAggregate
Description copied from class:Expression
Update an aggregate value. This method is called at statement execution time. It is usually called once for each row, but if the expression is used multiple times (for example in the column list, and as part of the HAVING expression) it is called multiple times - the row counter needs to be used to make sure the internal state is only updated once.- Specified by:
updateAggregate
in classExpression
- Parameters:
session
- the sessionstage
- select stage
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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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isConstant
public boolean isConstant()Description copied from class:Expression
Check if this expression will always return the same value.- Overrides:
isConstant
in classExpression
- Returns:
- if the expression is constant
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getSubexpressionCount
public int getSubexpressionCount()Description copied from class:Expression
Returns count of subexpressions.- Overrides:
getSubexpressionCount
in classExpression
- Returns:
- count of subexpressions
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getSubexpression
Description copied from class:Expression
Returns subexpression with specified index.- Overrides:
getSubexpression
in classExpression
- Parameters:
index
- 0-based index- Returns:
- subexpression with specified index, may be null
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isArray
public boolean isArray()
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