net.sf.basedb.core.query
Class CountExpression
java.lang.Object
net.sf.basedb.core.query.CountExpression
- All Implemented Interfaces:
- Expression, QueryElement
public class CountExpression
- extends Object
- implements Expression
Count the number of values: COUNT(e)
- Version:
- 2.0
- Author:
- Nicklas
- See Also:
Aggregations.count(Expression, boolean)
- Last modified
- $Date: 2010-04-21 11:48:29 +0200 (Wed, 21 Apr 2010) $
e
private final Expression e
distinct
private final boolean distinct
CountExpression
CountExpression(Expression e,
boolean distinct)
toQl
public String toQl(Query query,
DbControl dc)
throws BaseException
- Description copied from interface:
QueryElement
- Create a query language string of the query element. Use the
Query.getQueryType()
method to find out which query language is wanted
in case the element requires different syntax for different languages.
- Specified by:
toQl
in interface QueryElement
- Parameters:
query
- The query that is about to be executeddc
- The DbControl
object used to execute the query
- Throws:
BaseException
- If there is any other error
getChildren
public Collection<? extends QueryElement> getChildren()
- Description copied from interface:
QueryElement
- Get the children of this query element or null if it has no children.
For example the
AddExpression
has two children, the expression
beeing added.
- Specified by:
getChildren
in interface QueryElement
- Returns:
- The expression to count
toString
public String toString()
- Overrides:
toString
in class Object
equals
public boolean equals(Object other)
- This expression is equal to another CountExpression if their
child expressions are equal and have the same DISTINCT setting.
- Overrides:
equals
in class Object
hashCode
public int hashCode()
- Overrides:
hashCode
in class Object