标签:sel eid null 空格 ble cat 字段 bsp 合并
select concat(name,id) as name from table 这种将两列的结果拼在一起
select concat(concat(name,‘ ‘),id) as nameid,age from table 这种将两列的结果拼在一起,中间有空格隔开
select name+id as name from table 这种如果有一列的值为null 则结果为null
标签:sel eid null 空格 ble cat 字段 bsp 合并
原文地址:https://www.cnblogs.com/aikeming/p/11906286.html