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mysql 5 的 charset

原创 MySQL 作者:bulletming 时间:2019-06-16 22:42:05 0 删除 编辑

除了 server,database,table,column可以特定的指定字符集及校对排序规则外,还有connect,client,不过connect,client我就没去太看他,保持client和server的相同才可简化问题。

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10.3.1. Server Character Set and Collation
The current server character set and collation are available as the values of the character_set_server and collation_server system variables. These variables can be changed at runtime.


10.3.2. Database Character Set and Collation
The database character set and collation are used as default values if the table character set and collation are not specified in CREATE TABLE statements. They have no other purpose.

The character set and collation for the default database are available as the values of the character_set_database and collation_database system variables. The server sets these variables whenever the default database changes. If there is no default database, the variables have the same value as the corresponding server-level variables, character_set_server and collation_server.


10.3.3. Table Character Set and Collation
MySQL chooses the table character set and collation thus:

If both CHARACTER SET X and COLLATE Y were specified, then character set X and collation Y.

If CHARACTER SET X was specified without COLLATE, then character set X and its default collation.

Otherwise, the database character set and collation.

The table character set and collation are used as default values if the column character set and collation are not specified in individual column definitions. The table character set and collation are MySQL extensions; there are no such things in standard SQL.

10.3.4. Column Character Set and Collation
MySQL chooses the column character set and collation thus:

If both CHARACTER SET X and COLLATE Y were specified, then character set X and collation Y.

If CHARACTER SET X was specified without COLLATE, then character set X and its default collation.

Otherwise, the table character set and collation.

The CHARACTER SET and COLLATE clauses are standard SQL.

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