今天遇到了一個問題，想通過視圖將兩個表連接起來，其中一個表字段不全，這時候肯定合不到一起，如果加一個冗余字段也不合適，后來發(fā)現(xiàn)通過一個sql就可以實現(xiàn)，參考：

SELECT `agent_id` AS `agent_id`,? `distributor_id` AS `distributor_id`,? `serial_sn` AS `serial_sn`, `e_s_ledger_record`.`order_sn` AS `order_sn`,? `create_time` AS `create_time`,? `ledger_amount` AS `money`, 1 AS `type` FROM `e_s_ledger_record`

union

SELECT `agent_id` AS `agent_id`,? `distributor_id` AS `distributor_id`,? `withdraw_sn` AS `serial_sn`, '' AS `order_sn`,? `create_time` AS `create_time`,? `money` AS `money`, 2 AS `type` FROM `e_s_withdraw`

上邊sql是將兩個不同業(yè)務(wù)合到一起的，通過type區(qū)分進賬出賬，由于字段不統(tǒng)一，于是可以通過 “2 AS `type`” 實現(xiàn)，這樣最后的表里就會出現(xiàn)這個字段，且全部值都是2啦