文本

文本长度

SELECT CHAR_LENGTH('你好 mysql') AS length;

length
8

替换文本

SELECT REPLACE('你好 mysql 你好 sqlite', '你好', 'hello') AS result;

result
hello mysql hello sqlite

拼接文本

SELECT CONCAT('你好', 'mysql') AS result;

result
你好mysql

SELECT CONCAT_WS(' ', '你好', 'mysql') AS result;

result
你好 mysql

截断文本

SELECT SUBSTRING('你好 mysql', 4, 8) AS result;

result
mysql

SELECT LEFT('你好 mysql', 2) AS result;

result
你好

SELECT RIGHT('你好 mysql', 5) AS result;

result
mysql