SQL 必知必会(第三版)学习笔记

7.2
拼接字段
select n_progid||'test' from co_schedule;

去除多余的空格
select trim(' test ');默认去掉两端的空格
select trim(leading 'x' from 'xTomxx');
select trim(trailing 'x' from 'xTomxx');

别名
select n_progid||'test' as test from co_schedule;
select prod_id,quantity,item_price,quantity*item_price as total_price from orders ;

8.2
文本处理函数
upper() lower() length()