MySQL 5.7升級8.0后出現(xiàn)排序規(guī)則問題的解決方案匯總
比較操作中使用不同的字符集或排序規(guī)則通常會觸發(fā)此問題,MySQL 8.0 默認 COLLATE 為 utf8mb4_0900_ai_ci
和 對應列 COLLATE 的 utf8mb4_general_ci
不匹配。
問題現(xiàn)象
MySQL 5.7.34 升級到 8.0.32 后部分查詢語句報錯如下:
ERROR 1267 (HY000): Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation 'find_in_set'
問題原因
比較操作中使用不同的字符集或排序規(guī)則通常會觸發(fā)此問題,MySQL 8.0 默認 COLLATE 為 utf8mb4_0900_ai_ci
和 對應列 COLLATE 的 utf8mb4_general_ci
不匹配。
問題重現(xiàn)過程
創(chuàng)建測試表。
CREATE TABLE `t01` ( `ID` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, `A_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL, `B_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`ID`) USING BTREE ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC;
執(zhí)行查詢語句。
SELECT AAA.* FROM( SELECT @xxx AS _xxx, ( SELECT @xxx := GROUP_CONCAT( A_CODE ) FROM t01 WHERE FIND_IN_SET( B_CODE, @xxx ) ) AS cxxx FROM t01,( SELECT @xxx := 'xxx') b WHERE @xxx IS NOT NULL) ID,t01 AAA WHERE FIND_IN_SET( AAA.A_CODE, ID._xxx ) order by A_CODE;
報錯。
ERROR 1267 (HY000): Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation 'find_in_set'
問題分析
查看默認排序規(guī)則。
mysql> show collation like 'utf8mb4_0900_ai_ci'; +--------------------+---------+-----+---------+----------+---------+---------------+ | Collation | Charset | Id | Default | Compiled | Sortlen | Pad_attribute | +--------------------+---------+-----+---------+----------+---------+---------------+ | utf8mb4_0900_ai_ci | utf8mb4 | 255 | Yes | Yes | 0 | NO PAD | +--------------------+---------+-----+---------+----------+---------+---------------+ 1 row in set (0.00 sec) mysql> show collation like 'utf8mb4_general_ci'; +--------------------+---------+----+---------+----------+---------+---------------+ | Collation | Charset | Id | Default | Compiled | Sortlen | Pad_attribute | +--------------------+---------+----+---------+----------+---------+---------------+ | utf8mb4_general_ci | utf8mb4 | 45 | | Yes | 1 | PAD SPACE | +--------------------+---------+----+---------+----------+---------+---------------+ 1 row in set (0.00 sec) mysql> SELECT * FROM INFORMATION_SCHEMA.COLLATIONS WHERE IS_DEFAULT='Yes' and CHARACTER_SET_NAME='utf8mb4'; +--------------------+--------------------+-----+------------+-------------+---------+---------------+ | COLLATION_NAME | CHARACTER_SET_NAME | ID | IS_DEFAULT | IS_COMPILED | SORTLEN | PAD_ATTRIBUTE | +--------------------+--------------------+-----+------------+-------------+---------+---------------+ | utf8mb4_0900_ai_ci | utf8mb4 | 255 | Yes | Yes | 0 | NO PAD | +--------------------+--------------------+-----+------------+-------------+---------+---------------+ 1 row in set (0.00 sec)
查看相關參數(shù)。
mysql> show variables like '%collation%'; +-------------------------------+--------------------+ | Variable_name | Value | +-------------------------------+--------------------+ | collation_connection | utf8mb4_0900_ai_ci | | collation_database | utf8mb4_general_ci | | collation_server | utf8mb4_general_ci | | default_collation_for_utf8mb4 | utf8mb4_0900_ai_ci | +-------------------------------+--------------------+ 4 rows in set (0.00 sec) 其中: mysql> show global variables like '%collation%'; +-------------------------------+--------------------+ | Variable_name | Value | +-------------------------------+--------------------+ | collation_connection | utf8mb4_general_ci | | collation_database | utf8mb4_general_ci | | collation_server | utf8mb4_general_ci | | default_collation_for_utf8mb4 | utf8mb4_0900_ai_ci | +-------------------------------+--------------------+ 4 rows in set (0.00 sec)
查看配置文件參數(shù)。
mysql@CJC-DB-01:/home/mysql$cat /etc/my.cnf ...... [mysqld] collation_server = utf8mb4_general_ci
可以看到,客戶端局部會話變量 collation_connection 的值為 utf8mb4_0900_ai_ci
,而全局變量值為 utf8mb4_general_ci
,兩者不一致。
這是由于服務端在客戶端連接時,獲取了客戶端對字符集和排序規(guī)則的缺省設置,也就是 utf8mb4_0900_ai_ci
。
解決方案
- 修改參數(shù)
- 修改表 COLLATE
- 修改 SQL 語句
1. 修改參數(shù)
參數(shù)collation_connection
在客戶端局部變量值和全局變量值不一致,如何改成一致?官網(wǎng)參考材料
--character-set-client-handshake Command-Line Format:--character-set-client-handshake[={OFF|ON}] Deprecated:8.0.35 Type:Boolean Default Value:ON
參數(shù)說明
- 不忽略客戶端發(fā)送的字符集信息
- 為了忽略客戶端信息并使用默認的服務器字符集
- 使用參數(shù):
--skip-character-set-client-handshake
此選項在 MySQL 8.0.35 及更高版本的 MySQL 8.0 中已被棄用。在該版本中,無論何時使用此選項,都會發(fā)出警告,并將在未來版本的 MySQL 中刪除。
依賴此選項的應用程序應該盡快開始遷移。
添加 my.cnf 參數(shù)。
[mysqld] skip-character-set-client-handshake
重啟 MySQL。
mysqladmin -uroot -p****** shutdown mysqld --defaults-file=/etc/my.cnf --user=mysql & 登錄 mysql -uroot -p cjc 查看參數(shù),collation_connection 參數(shù)值修改成功 mysql> show global variables like '%collation%'; +-------------------------------+--------------------+ | Variable_name | Value | +-------------------------------+--------------------+ | collation_connection | utf8mb4_general_ci | | collation_database | utf8mb4_general_ci | | collation_server | utf8mb4_general_ci | | default_collation_for_utf8mb4 | utf8mb4_0900_ai_ci | +-------------------------------+--------------------+ 4 rows in set (0.00 sec) mysql> show variables like '%collation%'; +-------------------------------+--------------------+ | Variable_name | Value | +-------------------------------+--------------------+ | collation_connection | utf8mb4_general_ci | | collation_database | utf8mb4_general_ci | | collation_server | utf8mb4_general_ci | | default_collation_for_utf8mb4 | utf8mb4_0900_ai_ci | +-------------------------------+--------------------+ 4 rows in set (0.01 sec)
再次執(zhí)行,問題解決。
SELECT AAA.* FROM( SELECT @xxx AS _xxx, ( SELECT @xxx := GROUP_CONCAT( A_CODE ) FROM t01 WHERE FIND_IN_SET( B_CODE, @xxx ) ) AS cxxx FROM t01,( SELECT @xxx := 'xxx') b WHERE @xxx IS NOT NULL) ID,t01 AAA WHERE FIND_IN_SET( AAA.A_CODE, ID._xxx ) order by A_CODE; Empty set, 2 warnings (0.00 sec)
2. 修改表 COLLATE
先改回原參數(shù),查詢報錯。
SELECT AAA.* FROM( SELECT @xxx AS _xxx, ( SELECT @xxx := GROUP_CONCAT( A_CODE ) FROM t01 WHERE FIND_IN_SET( B_CODE, @xxx ) ) AS cxxx FROM t01,( SELECT @xxx := 'xxx') b WHERE @xxx IS NOT NULL) ID,t01 AAA WHERE FIND_IN_SET( AAA.A_CODE, ID._xxx ) order by A_CODE; ERROR 1267 (HY000): Illegal mix of collations (utf8mb4_general_ci,IMPLICIT) and (utf8mb4_0900_ai_ci,IMPLICIT) for operation 'find_in_set'
修改表排序規(guī)則。
mysql> show create table t01\G; *************************** 1. row *************************** Table: t01 Create Table: CREATE TABLE `t01` ( `ID` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, `A_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL, `B_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL, PRIMARY KEY (`ID`) USING BTREE ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC 1 row in set (0.00 sec) ERROR: No query specified
修改所有列 COLLATE,實際上只修改 A_CODE
、B_CODE
列 COLLATE 也可解決此問題。
ALTER TABLE cjc.t01 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci; ALTER TABLE cjc.t01 MODIFY COLUMN `ID` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL; ALTER TABLE cjc.t01 MODIFY COLUMN `A_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL; ALTER TABLE cjc.t01 MODIFY COLUMN `B_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL;
再次執(zhí)行,問題解決。
SELECT AAA.* FROM( SELECT @xxx AS _xxx, ( SELECT @xxx := GROUP_CONCAT( A_CODE ) FROM t01 WHERE FIND_IN_SET( B_CODE, @xxx ) ) AS cxxx FROM t01,( SELECT @xxx := 'xxx') b WHERE @xxx IS NOT NULL) ID,t01 AAA WHERE FIND_IN_SET( AAA.A_CODE, ID._xxx ) order by A_CODE; Empty set, 2 warnings (0.00 sec)
查看表結構。
mysql> show create table t01\G; *************************** 1. row *************************** Table: t01 Create Table: CREATE TABLE `t01` ( `ID` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL, `A_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL, `B_CODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL, PRIMARY KEY (`ID`) USING BTREE ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci ROW_FORMAT=DYNAMIC 1 row in set (0.00 sec)
3. 修改 SQL 語句
將 A_CODE
,B_CODE
列的 COLLATE 在 SQL 語句中轉換為 utf8mb4_0900_ai_ci
。
改寫后的SQL如下:
SELECT AAA.* FROM( SELECT @xxx AS _xxx, ( SELECT @xxx := GROUP_CONCAT( A_CODE COLLATE utf8mb4_0900_ai_ci ) FROM t01 WHERE FIND_IN_SET( B_CODE COLLATE utf8mb4_0900_ai_ci, @xxx ) ) AS cxxx FROM t01,( SELECT @xxx := 'xxx') b WHERE @xxx IS NOT NULL) ID,t01 AAA WHERE FIND_IN_SET( AAA.A_CODE COLLATE utf8mb4_0900_ai_ci, ID._xxx ) order by A_CODE;
總結
比較三種解決方案,每種解決方案適用場景不同,請根據(jù)實際情況選擇解決方案。
修改參數(shù)
適用于數(shù)據(jù)庫是從 5.7 或更低版本升級到 8.0,并且表數(shù)量較多、數(shù)據(jù)量加大。不適用于批量修改所有表、列字符集和排序規(guī)則。
修改表 COLLATE
適用于修改過程會鎖表,數(shù)據(jù)量越大時間越長,使用于數(shù)據(jù)量小的場景,建議將所有表、列字符集和排序規(guī)則改成 8.0 默認值,后續(xù)新增表時不指定字符集和排序規(guī)則。
修改 SQL 語句
適用于臨時查詢,改SQL影響最小。
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