SUBSTRING_INDEX(str,delim,count)
按标识符截取指定长度的字符串
1 mysql> SELECT SUBSTRING_INDEX(‘www.mysql.com‘, ‘.‘, 2); 2 -> ‘www.mysql‘ 3 mysql> SELECT SUBSTRING_INDEX(‘www.mysql.com‘, ‘.‘, -2); 4 -> ‘mysql.com‘
TRIM([{BOTH | LEADING | TRAILING} [, remstr] FROM] str)TRIM([remstr FROM] str)
删除字符串前后的特定字符或者字符串，默认删除空格，默认两端都删
1 mysql> SELECT TRIM(‘ bar ‘); 2 -> ‘bar‘ 3 mysql> SELECT TRIM(LEADING ‘x‘ FROM ‘xxxbarxxx‘); 4 -> ‘barxxx‘ 5 mysql> SELECT TRIM(BOTH ‘x‘ FROM ‘xxxbarxxx‘); 6 -> ‘bar‘ 7 mysql> SELECT TRIM(TRAILING ‘xyz‘ FROM ‘barxxyz‘); 8 -> ‘barx‘
连接子字符串，如果有一个字符串为空，将返回NULL
1 mysql> SELECT CONCAT(‘My‘, ‘S‘, ‘QL‘); 2 -> ‘MySQL‘ 3 mysql> SELECT CONCAT(‘My‘, NULL, ‘QL‘); 4 -> NULL 5 mysql> SELECT CONCAT(14.3); 6 -> ‘14.3‘ 7 mysql> SELECT ‘My‘ ‘S‘ ‘QL‘; 8 -> ‘MySQL‘
1 mysql> SELECT FORMAT(12332.123456, 4); 2 -> ‘12,332.1235‘ 3 mysql> SELECT FORMAT(12332.1,4); 4 -> ‘12,332.1000‘ 5 mysql> SELECT FORMAT(12332.2,0); 6 -> ‘12,332‘ 7 mysql> SELECT FORMAT(12332.2,2,‘de_DE‘); 8 -> ‘12.332,20‘
原文：http://www.cnblogs.com/hzj680539/p/5054939.html