MySQL view character set and proofing rules

About SQL Keywords and function names are not case sensitive , But whether the data value is case sensitive , And character sets and proofreading rules .

_ci（ Case insensitive ）,_cs（ Case sensitive ）,_bin（ binary , That is, the comparison is based on the value of character encoding and language irrelevant ）

• View all character sets and proofreading rules
  
• see GBK and UTF-8 Proofreading rules for character sets

show collation like ‘gbk%’;

show collation like ‘utf8%’;

• utf8_unicode_ci and utf8_general_ci Alignment 、 There is no real difference in English .
• utf8_general_ci Fast proofreading , But the accuracy is a little bit poor .
• utf8_unicode_ci High accuracy , But proofreading is a little slow .

If your application has German 、 French or Russian , Be sure to use utf8_unicode_ci. It's usually used utf8_general_ci That's enough .

• View the server's character set and proofreading rules
  
• View and modify the character set and proofreading rules of a database
  
  or
  

Modify the character set and proofreading rules of the database ：

ALTER DATABASE Database name DEFAULT CHARACTER SET Character set name 【COLLATE Name of proofreading rule 】;

for example ：
ALTER DATABASE ceshi_db DEFAULT CHARACTER SET utf8 collate utf8_general_ci;

Be careful ： After modifying the default character set and proofreading rules of the database , The character set and proofreading rules of the original created table will not change , if necessary , Then it needs to be modified separately .

• View the character set and proofreading rules of a table

View character set ：show create table users;

If you want to see proofreading rules ：show table status from bookstore like ‘%users%’ ;

Modify the character set and proofreading rules of a table ：
Modify the default character set of the table ：

ALTER TABLE The name of the table DEFAULT CHARACTER SET Character set name 【COLLATE Name of proofreading rule 】;

Set the default character set and all character columns （CHAR,VARCHAR,TEXT） Change to a new character set ：

ALTER TABLE The name of the table CONVERT TO CHARACTER SET Character set name 【COLLATE Name of proofreading rule 】;

for example ：ALTER TABLE ceshi_table DEFAULT CHARACTER SET gbk collate gbk_chinese_ci;