CountFunction

java.lang.Object
- org.datanucleus.store.rdbms.sql.method.CountFunction

All Implemented Interfaces:

SQLMethod
```
public class CountFunction
extends java.lang.Object
implements SQLMethod
```
Expression handler to invoke the SQL COUNT aggregation function. For use in evaluating COUNT({expr}) where the RDBMS supports this function. Returns a NumericExpression "COUNT({numericExpr})".

Constructor Summary

Constructors
Constructor Description

CountFunction()

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`SQLExpression`	`getExpression(SQLStatement stmt, SQLExpression expr, java.util.List<SQLExpression> args)`	Return the expression for this SQL function.
`protected java.lang.String`	`getFunctionName()`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - CountFunction
```
public CountFunction()
```
- Method Detail
  - getFunctionName
```
protected java.lang.String getFunctionName()
```
  - getExpression
```
public SQLExpression getExpression(SQLStatement stmt,
                                   SQLExpression expr,
                                   java.util.List<SQLExpression> args)
```
    Description copied from interface: SQLMethod
    
    Return the expression for this SQL function.
    
    Specified by:
    
    getExpression in interface SQLMethod
    
    Parameters:
    
    stmt - SQLStatement that this expression is for
    
    expr - The expression that it is invoked on
    
    args - Arguments passed in
    
    Returns:
    
    The SQL expression using the SQL function