sql_delegate_method 87 __sql__ Delegate Method return to [[Delegate class methods]] ===Synopsis=== The __sql__ delegate class method can be defined in any delegate class to specify the SQL query that should be used to fetch records for a given table. This method overrides the [[__sql__]] directive of the fields.ini file. This strategy is primarily used to graft columns from another table onto the base table. =====Use Caution===== This is an advanced feature and, if used incorrectly, can muck up your application. Make sure that your SQL query includes a superset of the columns in the base table, and is a row-for-row match for the rows in the base table. I.e. you should never use an internal join. Always use a left join so that all of the rows of the base table are returned even if the join table doesn't have a corresponding row. If you want to simply filter a table's records, and don't need to graft any additional columns onto the table, you should use the [[setSecurityFilters]] method. ===Example=== Given the table foo, its delegate class: <code> class tables_foo { function __sql__(){ return "select f.*, c.category_name from foo f left join categories c on f.category_id=c.category_id"; } } </code> This effectively grafts a column "category_name" onto the foo table based on a join with the categories table. __sql__, SQL queries, delegate class en