通过sql和codeigniter检索数据

Question

当我使用这个sql时，第一个表中mem_name的结果被重复了很多我怎么能修复它

    <?php     
    $sql="SELECT mc.mc_id,mc.mc_role,mc.mc_order,mc.mc_order IS NULL AS isnull, mem.*
                    FROM $this->memberCatsTableName mc, $this->tableName mem

                    WHERE mc.cat_id=$cat_id $where  AND mc.member_id=mem.mem_id or mem.mem_name='$mem_name'

                    ORDER BY isnull ASC, mc.mc_order ASC";

            $query = $this->db->query($sql);
            return $query->result_array();
?>

Answer 1

这里是修改过的查询..

<?php     
    $sql="SELECT mc.mc_id,mc.mc_role,mc.mc_order,mc.mc_order IS NULL AS isnull, mem.*
                    FROM $this->memberCatsTableName mc, $this->tableName mem

                    WHERE mc.cat_id=$cat_id $where  AND mc.member_id=mem.mem_id or mem.mem_name='$mem_name' 

       Group by mem.mem_name 

                    ORDER BY isnull ASC, mc.mc_order ASC";

            $query = $this->db->query($sql);
            return $query->result_array();
?>

您可以按查询进行分组..

Or you can also specify the join criteria

希望它有所帮助。

Answer 2

您必须指定加入条件。