SQL Server 2016 函数：LEFT、RIGHT

• LEFT 返回字符串中从左边开始指定个数字符

LEFT(character_expression,integer_expression);

• RIGTH 返回字符串从右边开始指定个数字符

RIGHT(character_expression,integer_expression);

SELECT LEFT('abcedf',3);  -- 返回从左侧数前 3 个字符，第二个参数不接收负数，会报错

SELECT RIGHT('abcedf',3);  -- 返回从右侧数前 3 个字符


SELECT * FROM Subject WHERE ID=4;

SELECT *,LEFT(Description,10) AS New_Description FROM Subject WHERE ID=4;

SELECT *,RIGHT(Description,10) AS New_Description FROM Subject WHERE ID=4;