mysql中怎么测试varchar类型最大长度

本篇文章为大家展示了mysql中怎么测试varchar类型最大长度，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。

1.先看字符集为latin1时，每个字符应该是占据一个byte
mysql> create table test(a varchar(65535)) engine=innodb charset=latin1;
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

mysql> create table test(a varchar(65533)) engine=innodb charset=latin1;
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

mysql> create table test(a varchar(65532)) engine=innodb charset=latin1;
Query OK, 0 rows affected (0.01 sec)

2.再看字符集为GBK时，每个字符应该占据2个byte
mysql> drop table test;
Query OK, 0 rows affected (0.00 sec)

mysql> create table test(a varchar(32767)) engine=innodb charset=gbk;
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

mysql> create table test(a varchar(32766)) engine=innodb charset=gbk;
Query OK, 0 rows affected (0.00 sec)

3.当字符集为UTF8时，每个字符占据了3个byte
mysql> drop table test;
Query OK, 0 rows affected (0.00 sec)

mysql> create table test(a varchar(65535)) engine=innodb charset=utf8;
ERROR 1074 (42000): Column length too big for column 'a' (max = 21845); use BLOB or TEXT instead

mysql> create table test(a varchar(21845)) engine=innodb charset=utf8;
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

mysql> create table test(a varchar(21844)) engine=innodb charset=utf8;
Query OK, 0 rows affected (0.00 sec)


最后，如果表中所有varchar类型的列长度总和超过了65535，创建表时也会报错
mysql> drop table test;
Query OK, 0 rows affected (0.00 sec)

mysql> create table test(a varchar(22000),b varchar(22000),c varchar(22000)) charset=latin1 engine=innodb;
ERROR 1118 (42000): Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

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