Package org.h2.expression.condition
Class Comparison
- java.lang.Object
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- org.h2.expression.Expression
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- org.h2.expression.condition.Condition
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- org.h2.expression.condition.Comparison
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Field Summary
Fields Modifier and Type Field Description static int
BIGGER
The comparison type meaning > as in ID>1.static int
BIGGER_EQUAL
The comparison type meaning >= as in ID>=1.(package private) static java.lang.String[]
COMPARE_TYPES
private int
compareType
static int
EQUAL
The comparison type meaning = as in ID=1.static int
EQUAL_NULL_SAFE
The comparison type meaning ID IS NOT DISTINCT FROM 1.static int
FALSE
This is a pseudo comparison type that is only used for index conditions.static int
IN_LIST
This is a pseudo comparison type that is only used for index conditions.static int
IN_QUERY
This is a pseudo comparison type that is only used for index conditions.private Expression
left
static int
NOT_EQUAL
The comparison type meaning <> as in ID<>1.static int
NOT_EQUAL_NULL_SAFE
The comparison type meaning ID IS DISTINCT FROM 1.private Expression
right
static int
SMALLER
The comparison type meaning < as in ID<1.static int
SMALLER_EQUAL
The comparison type meaning <= as in ID<=1.static int
SPATIAL_INTERSECTS
This is a comparison type that is only used for spatial index conditions (operator "&&").private boolean
whenOperand
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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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Constructor Summary
Constructors Constructor Description Comparison(int compareType, Expression left, Expression right, boolean whenOperand)
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description (package private) static Value
compare(SessionLocal session, Value l, Value r, int compareType)
Compare two values.void
createIndexConditions(SessionLocal session, TableFilter filter)
Create index conditions if possible and attach them to the table filter.(package private) static void
createIndexConditions(TableFilter filter, Expression left, Expression right, int compareType)
(package private) Expression
getAdditionalAnd(SessionLocal session, Comparison other)
Get an additional condition if possible.private static ConditionIn
getConditionIn(Expression left, Expression value1, Expression value2)
int
getCost()
Estimate the cost to process the expression.(package private) Expression
getIfEquals(Expression match)
Get the other expression if this is an equals comparison and the other expression matches.private int
getNotCompareType()
Expression
getNotIfPossible(SessionLocal session)
If it is possible, return the negated expression.private static int
getReversedCompareType(int type)
Expression
getSubexpression(int index)
Returns subexpression with specified index.int
getSubexpressionCount()
Returns count of subexpressions.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.java.lang.StringBuilder
getWhenSQL(java.lang.StringBuilder builder, int sqlFlags)
Appends the SQL statement of this when operand to the specified builder.boolean
getWhenValue(SessionLocal session, Value left)
Return the resulting value of when operand for the current row.boolean
isEverything(ExpressionVisitor visitor)
Check if this expression and all sub-expressions can fulfill a criteria.boolean
isWhenConditionOperand()
Returns whether this expression is a right side of condition in a when operand.void
mapColumns(ColumnResolver resolver, int level, int state)
Map the columns of the resolver to expression columns.boolean
needParentheses()
Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.Expression
optimize(SessionLocal session)
Try to optimize the expression.(package private) Expression
optimizeOr(SessionLocal session, Comparison other)
Replace the OR condition with IN condition if possible.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.condition.Condition
castToBoolean, getType
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Methods inherited from class org.h2.expression.Expression
addFilterConditions, getAlias, getBooleanValue, getColumnName, getColumnNameForView, getEnclosedSQL, getNonAliasExpression, getNullable, getSchemaName, getSQL, getSQL, getSQL, getSQL, getTableAlias, getTableName, isConstant, isIdentity, isNullConstant, isValueSet, 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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EQUAL
public static final int EQUAL
The comparison type meaning = as in ID=1.- See Also:
- Constant Field Values
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NOT_EQUAL
public static final int NOT_EQUAL
The comparison type meaning <> as in ID<>1.- See Also:
- Constant Field Values
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SMALLER
public static final int SMALLER
The comparison type meaning < as in ID<1.- See Also:
- Constant Field Values
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BIGGER
public static final int BIGGER
The comparison type meaning > as in ID>1.- See Also:
- Constant Field Values
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SMALLER_EQUAL
public static final int SMALLER_EQUAL
The comparison type meaning <= as in ID<=1.- See Also:
- Constant Field Values
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BIGGER_EQUAL
public static final int BIGGER_EQUAL
The comparison type meaning >= as in ID>=1.- See Also:
- Constant Field Values
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EQUAL_NULL_SAFE
public static final int EQUAL_NULL_SAFE
The comparison type meaning ID IS NOT DISTINCT FROM 1.- See Also:
- Constant Field Values
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NOT_EQUAL_NULL_SAFE
public static final int NOT_EQUAL_NULL_SAFE
The comparison type meaning ID IS DISTINCT FROM 1.- See Also:
- Constant Field Values
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SPATIAL_INTERSECTS
public static final int SPATIAL_INTERSECTS
This is a comparison type that is only used for spatial index conditions (operator "&&").- See Also:
- Constant Field Values
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COMPARE_TYPES
static final java.lang.String[] COMPARE_TYPES
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FALSE
public static final int FALSE
This is a pseudo comparison type that is only used for index conditions. It means the comparison will always yield FALSE. Example: 1=0.- See Also:
- Constant Field Values
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IN_LIST
public static final int IN_LIST
This is a pseudo comparison type that is only used for index conditions. It means equals any value of a list. Example: IN(1, 2, 3).- See Also:
- Constant Field Values
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IN_QUERY
public static final int IN_QUERY
This is a pseudo comparison type that is only used for index conditions. It means equals any value of a list. Example: IN(SELECT ...).- See Also:
- Constant Field Values
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compareType
private int compareType
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left
private Expression left
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right
private Expression right
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whenOperand
private final boolean whenOperand
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Constructor Detail
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Comparison
public Comparison(int compareType, Expression left, Expression right, boolean whenOperand)
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Method Detail
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needParentheses
public boolean needParentheses()
Description copied from class:Expression
Returns whether this expressions needs to be wrapped in parentheses when it is used as an argument of other expressions.- Overrides:
needParentheses
in classExpression
- Returns:
true
if it is
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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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getWhenSQL
public java.lang.StringBuilder getWhenSQL(java.lang.StringBuilder builder, int sqlFlags)
Description copied from class:Expression
Appends the SQL statement of this when operand to the specified builder.- Overrides:
getWhenSQL
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.- Specified by:
optimize
in classExpression
- Parameters:
session
- the session- Returns:
- the optimized expression
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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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getWhenValue
public boolean getWhenValue(SessionLocal session, Value left)
Description copied from class:Expression
Return the resulting value of when operand for the current row.- Overrides:
getWhenValue
in classExpression
- Parameters:
session
- the sessionleft
- value on the left side- Returns:
- the result
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compare
static Value compare(SessionLocal session, Value l, Value r, int compareType)
Compare two values.- Parameters:
session
- the sessionl
- the first valuer
- the second valuecompareType
- the compare type- Returns:
- result of comparison, either TRUE, FALSE, or NULL
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isWhenConditionOperand
public boolean isWhenConditionOperand()
Description copied from class:Expression
Returns whether this expression is a right side of condition in a when operand.- Overrides:
isWhenConditionOperand
in classExpression
- Returns:
true
if it is,false
otherwise
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getReversedCompareType
private static int getReversedCompareType(int type)
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getNotIfPossible
public Expression getNotIfPossible(SessionLocal session)
Description copied from class:Expression
If it is possible, return the negated expression. This is used to optimize NOT expressions: NOT ID>10 can be converted to ID<=10. Returns null if negating is not possible.- Overrides:
getNotIfPossible
in classExpression
- Parameters:
session
- the session- Returns:
- the negated expression, or null
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getNotCompareType
private int getNotCompareType()
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createIndexConditions
public void createIndexConditions(SessionLocal session, TableFilter filter)
Description copied from class:Expression
Create index conditions if possible and attach them to the table filter.- Overrides:
createIndexConditions
in classExpression
- Parameters:
session
- the sessionfilter
- the table filter
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createIndexConditions
static void createIndexConditions(TableFilter filter, Expression left, Expression right, int compareType)
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setEvaluatable
public void setEvaluatable(TableFilter tableFilter, boolean b)
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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updateAggregate
public void updateAggregate(SessionLocal session, int stage)
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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mapColumns
public void mapColumns(ColumnResolver resolver, int level, int state)
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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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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getIfEquals
Expression getIfEquals(Expression match)
Get the other expression if this is an equals comparison and the other expression matches.- Parameters:
match
- the expression that should match- Returns:
- null if no match, the other expression if there is a match
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getAdditionalAnd
Expression getAdditionalAnd(SessionLocal session, Comparison other)
Get an additional condition if possible. Example: given two conditions A=B AND B=C, the new condition A=C is returned.- Parameters:
session
- the sessionother
- the second condition- Returns:
- null or the third condition for indexes
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optimizeOr
Expression optimizeOr(SessionLocal session, Comparison other)
Replace the OR condition with IN condition if possible. Example: given the two conditions A=1 OR A=2, the new condition A IN(1, 2) is returned.- Parameters:
session
- the sessionother
- the second condition- Returns:
- null or the joined IN condition
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getConditionIn
private static ConditionIn getConditionIn(Expression left, Expression value1, Expression value2)
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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
public Expression getSubexpression(int index)
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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