mysql> UPDATE EACONTACTGROUPS A
SET GROUPNAME=(SELECT CONCAT(B.GROUPNAME,'-',A.GROUPNAME) FROM EACONTACTGROUPS B WHERE B.CORPID=A.CORPID AND B.USERID=A.USERID AND B.GROUPID=A.PARENTGROUPID)
WHERE A.PARENTGROUPID IS NOT NULL;
ERROR 1093 (HY000): You can't specify target table 'A' for update in FROM clause
涓婇潰鏄洰鍓峂YSQL5.0浠嶇劧鏈夌殑闄愬埗錛屾枃妗ｄ腑璇達細
In general, you cannot modify a table and select from the same table in a subquery. For example, this limitation applies to statements of the following forms:
DELETE FROM t WHERE ... (SELECT ... FROM t ...);UPDATE t ... WHERE col = (SELECT ... FROM t ...);{INSERT|REPLACE} INTO t (SELECT ... FROM t ...);
Exception: The preceding prohibition does not apply if you are using a subquery for the modified table in the
FROM
clause. Example:
UPDATE t ... WHERE col = (SELECT (SELECT ... FROM t...) AS _t ...);
Here the prohibition does not apply because a subquery in the
FROM
clause is materialized as a temporary table, so the relevant rows in
t
have already been selected by the time the update to
t
takes place. 渚濇嵁鏂囨。錛屾敼鎴愪笅闈㈢殑鏍峰瓙灝辮浜嗭細
mysql> UPDATE EACONTACTGROUPS A
SET GROUPNAME=(SELECT CONCAT(B.GROUPNAME,'-',A.GROUPNAME) FROM ( SELECT GROUPNAME,CORPID,USERID,GROUPID,PARENTGROUPID FROM EACONTACTGROUPS) B
WHERE B.CORPID=A.CORPID AND B.USERID=A.USERID AND B.GROUPID=A.PARENTGROUPID)
WHERE A.PARENTGROUPID IS NOT NULL;
Query OK, 16 rows affected (0.01 sec)
Rows matched: 16 Changed: 16 Warnings: 0
娉?浠婂ぉ鍐欎竴涓垹闄よ鍙ユ椂鎵懼埌鐨勪竴鐐硅祫鏂?瑙ｅ喅浜嗕竴涓畝鍗曠殑鍒犻櫎璇彞.鍛靛懙,浠ュ悗娉ㄦ剰浜?
鍘熷彞:delete from menu_item where parent_id =(select menu_item_id from menu_item where menu_data like '%manageVendors%');
淇敼鍚?delete from menu_item where parent_id =(select temp.menu_item_id from (select m.menu_item_id,m.menu_data from menu_item m) temp where temp.menu_data like '%manageVendors%');
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1銆佸鍑烘暩鎿氬簱鐐篸bname鐨勮〃緇撴瀯錛堝叾涓敤鎴跺悕鐐簉oot,瀵嗙爜鐐篸bpasswd,鐢熸垚鐨勮剼鏈悕鐐篸b.sql錛?br /> mysqldump -uroot -pdbpasswd -d dbname >db.sql;
2銆佸鍑烘暩鎿氬簱鐐篸bname鏌愬紶琛?test)緇撴瀯
mysqldump -uroot -pdbpasswd -d dbname test>db.sql;
3銆佸鍑烘暩鎿氬簱鐐篸bname鎵鏈夎〃緇撴瀯鍙婅〃鏁告摎錛堜笉鍔?d錛?br /> mysqldump -uroot -pdbpasswd dbname >db.sql;
4銆佸鍑烘暩鎿氬簱鐐篸bname鏌愬紶琛?test)緇撴瀯鍙婅〃鏁告摎錛堜笉鍔?d錛?br /> mysqldump -uroot -pdbpasswd dbname test>db.sql;
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寰堜箙娌掔敤鏁告摎搴簡錛屽鐨勭珶鐒墮ｆ壒閲忔彃琛ㄩ兘蹇樿浜嗐傚湪閫欓噷璁板綍涓涓嬨?/p>
鎶婅〃B涓殑瀛楁錛屾彃鍏ュ埌琛ˋ涓紱
INSERT INTO 琛ˋ(瀛楁鍚?, 瀛楁鍚?, ……) SELECT (瀛楁鍚?, 瀛楁鍚?, ……) FROM 琛˙;
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錛?錛塂ELETE鍙互閫氳繃WHERE璇彞閫夋嫨瑕佸垹闄ょ殑璁板綍銆備絾鎵ц寰楅熷害涓嶅揩錛屽彲浠ヨ繑鍥炶鍒犻櫎鐨勮褰曟暟銆傝孴RUNCATE TABLE鏃犳硶鍒犻櫎鎸囧畾鐨勮褰曪紝鑰屼笖涓嶈兘榪斿洖琚垹闄ょ殑璁板綍銆備絾瀹冩墽琛屽緱闈炲父蹇?br /> 錛?錛夊垎鍒墽琛?/font>DELETE FROM Table_name涓?/font>TRUNCATE TABLE Table_name
瀵規墽琛?/font>TRUNCATE TABLE Table_name鍚庯紝Table_name涓?/font>鑷嫻佹按浠庢柊寮濮嬭綆楋紝鑰?/font>DELETE FROM Table_name鍒欎笉浼氫粠鏂板紑濮嬶紝浼氱戶緇箣鍓嶇殑嫻佹按鍙楓?/font>
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