Class CountFunction

java.lang.Object
org.datanucleus.store.rdbms.sql.method.CountFunction
All Implemented Interfaces:
SQLMethod

public class CountFunction extends 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 Details

    • CountFunction

      public CountFunction()
  • Method Details

    • getFunctionName

      protected String getFunctionName()
    • getExpression

      public SQLExpression getExpression(SQLStatement stmt, SQLExpression expr, 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