Solution 2: Add primry key in your table then you can easily remove duplicates from your table using below query: DELETEFROMmemberWHEREidIN(SELECT*FROM(SELECTidFROMmemberGROUPBYmember_id, quiz_num, question_num, answer_numHAVING(COUNT(*)>1) )ASA ); Solution 3: SELECTDISTINCT*INTOTableA_Ver...
"to": "semijoin", "chosen": true } } ] "expanded_query": "/* select#1 */ select `t_table_1`.`id` AS `id`,`t_table_1`.`task_id` AS `task_id` from `t_table_1` semi join (`t_table_2`) where (1 and (`t_table_2`.`uid` = 1) and (`t_table_1`.`task_id` =...
再执行pt-duplicate-key-checker给出的解决方案 mysql [localhost:5727] {root} (sbtest) > ALTER TABLE `sbtest`.`sbtest1` DROP INDEX `id`; Query OK, 0 rows affected (0.01 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql [localhost:5727] {root} (sbtest) > ALTER TABLE `sbtest`.`sbtes...
消息:%s在第%d行靠近“%s” 错误号:1065; 符号: ER_EMPTY_QUERY; SQLSTATE: 42000 消息:查询为空 错误号:1066; 符号: ER_NONUNIQ_TABLE; SQLSTATE: 42000 消息:不是唯一的表/别名:'%s' 错误号:1067; 符号: ER_INVALID_DEFAULT; SQLSTATE: 42000 消息:“%s”的默认值无效 错误号:1068; 符号: ER_MU...
Fragmentation: Frequent deletions can lead to data fragmentation, where empty spaces are left in the database file. This fragmentation can impact query performance and should be periodically addressed through optimization techniques like defragmentation. Cascading effects: Deleting records might trigger casc...
"expanded_query":"/* select#2 */ select `t_table_2`.`id` from `t_table_2` where (`t_table_2`.`uid` = 1)" }, { "transformation": { "select#":2, "from":"IN (SELECT)", "to":"semijoin", "chosen":false } },
• Error number: 1063; Symbol: ER_WRONG_FIELD_SPEC; SQLSTATE: 42000 Message: Incorrect column specifier for column '%s' • Error number: 1064; Symbol: ER_PARSE_ERROR; SQLSTATE: 42000 Message: %s near '%s' at line %d 7 • Error number: 1065; Symbol: ER_EMPTY_QUERY; SQLSTATE: ...
sbtest1 add column e int not null default 0; Query OK, 0 rows affected (0.03 sec) Records...
void awake (THD::killed_state state_to_set) Awake a thread. More... void disconnect (bool server_shutdown=false) Disconnect the associated communication endpoint. More... int binlog_query (enum_binlog_query_type qtype, const char *query, size_t query_len...
mysql>createtablet(c1json);QueryOK,0rowsaffected(0.09sec)mysql>insertintotvalues('{ "name":"John", "age":30, "city":"New York"}');QueryOK,1rowaffected(0.01sec)mysql>selectc1->"$.age"fromt;+---+|c1->"$.age"|+---+|30|+---+1rowinset(0.00sec) 本文将从以下几个方面展开: 什...