mysql中的 case when 用法（张艳冲的博客）

    $sql = "SELECT A.id,A.ads_name,B.link_person AS user_name,A.cost_type,
                CASE
                    WHEN A.cost_type = '1' THEN A.min_cpc_price
                    WHEN A.cost_type = '2' THEN A.min_cpm_price
                    WHEN A.cost_type = '3' THEN A.cpa_price
                    ELSE A.cps_pecent
                END AS price,
                A.push_begin_time,A.push_end_time
                FROM lm_commercial_info A
                LEFT JOIN lm_user_info B ON B.id = A.user_id
                LEFT JOIN lm_commercial_ceativity_info C ON C.commercial_id = A.id
                LEFT JOIN lm_commercial_push_target D ON D.commercial_id = A.id";




 认真看一下吧