(1, '张三', 95) ON DUPLICATE KEY UPDATE score = 95; -- 从其他表插入数据 INSERT INTO students_backup SELECT * FROM students WHERE class = '计算机科学1班'; -- 忽略错误继续执行 INSERT IGNORE INTO students (id, name, age) VALUES (1, '张三', 20); 实际应用场景当新学生入学时,需要将...
1. CREATE TABLE ... AS SELECT statement to copy the source table column attributes and data, but without indexes and constraints. CREATE TABLE copy_table AS SELECT * FROM source_table; 2. CREATE TABLE ... LIKE statement to create an empty table based on the definition of the original tab...
数据入库这块有离线和实时两套入库系统,写同一个db的同一批mysql表,两边用的都是insert into table on duplicate key update这种方式。实时一直运行,离线5分钟更新一次,当两套系统同时运行时出现了死锁问题,频率还挺高。事务的隔离级别是read committed 读提交。 原因分析&解决方案 这里面分两种情况,一种是带主键的...
为了防止其它事务更新或者删除这条记录、或者往这条记录前面的间隙里插入记录,开始检查工作之前,MySQL 会对这条记录加共享锁。 而当insert语句带上on duplicate key update这个小尾巴时,这个小尾巴的作用是发现冲突记录时执行更新操作,既然是更新操作则需要加排他锁,所以这种情况下发生唯一键冲突,就直接加排他锁。 更...
1.String Data Type Syntax In some cases, MySQL may change a string column to a type different from that given in a CREATE TABLE or ALTER TABLE statement. For definitions of character string columns (CHAR, VARCHAR, and the TEXT types), MySQL interprets【ɪnˈtɜːrprəts诠释;说明...
#define ER_DUP_KEY 1022 "Can't write, duplicate key in table '%-.64s'", #define ER_ERROR_ON_CLOSE 1023 "Error on close of '%-.64s' (errno: %d)", #define ER_ERROR_ON_READ 1024 "Error reading file '%-.64s' (errno: %d)", ...
Last_SQL_Error: Error 'Duplicate entry '8' for key 'PRIMARY'' on query. Default database: 'mydb'.Query: 'insert into mytable VALUES ('8', 'George')'Skip_Counter: 0Retrieved_Gtid_Set: 38f32e23480a7-32a1-c323f78067fd37821: 1-8Auto_Position: 1You execute a "SHOW CREATE TABLE my...
DROP TABLE IF EXISTS table1, table2, table3;Copy TheIF EXISTSoption shows one warning astable1does not exist. Other tables are deleted. Note:Consider identifyingduplicate values in MySQL databasesand then deleting them to improve data efficiency. ...
If you are running into character set or collation problems, please refer to the following KB on how to convert toutf8character set withutf8_bincollation at the database, table, and column levels:How to Fix the Collation and Character Set of a MySQL Database. ...
For more information, see Section 13.1.18.4, “CREATE TABLE ... SELECT Statement”. IGNORE | REPLACE The IGNORE and REPLACE options indicate how to handle rows that duplicate unique key values when copying a table using a SELECT statement. For more information, see Section 13.1.18.4, “...