mysql sql 語句 查詢重複資料 並刪除重複資料 只保留一條
阿新 • • 發佈:2019-02-07
**#例1:根據手機號customer_id查詢所有重複的資料** SELECT * FROM aad_apply_main WHERE customer_id IN ( SELECT customer_id FROM aad_apply_main GROUP BY customer_id HAVING count(customer_id) > 1 ) ORDER BY customer_id DESC ; #例2:根據手機號customer_id刪除重複資料且只保留一條 DELETE FROM aad_apply_main WHERE stdmerno='***' AND customer_id IN (SELECT * FROM (SELECT customer_id FROM aad_apply_main WHERE stdmerno='***' GROUP BY customer_id HAVING COUNT(customer_id) > 1) t1) AND apply_no NOT IN (SELECT * FROM (SELECT MIN(apply_no) FROM aad_apply_main WHERE stdmerno='***' GROUP BY customer_id HAVING COUNT(customer_id) > 1) t2)
**欄位解釋:**
customer_id : 根據此欄位的重複來刪除資料;
stdmerno : 根據此欄位來約束需要去重複的物件
apply_no : 此欄位為表的主鍵id欄位