仅从左联接的表中选择一些列

本文介绍了仅从左联接的表中选择一些列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

是否可以在 LEFT JOIN 的表中只选择一些列?

Is it possible to select only some columns from a table on a LEFT JOIN?

推荐答案

当然.只需像在任何查询中一样列出您要选择的列:

Of course. Just list the columns you want to select as you would in any query:

SELECT table1.column1, table1.column2, table2.column3 FROM table1 LEFT JOIN table2 ON (...)

请注意，我在所有列中都包含了 table1. 或 table2. 前缀，以确保在其中存在同名字段时不会出现任何歧义两个表.

Note that I've included the table1. or table2. prefix on all columns to be sure there aren't any ambiguities where fields with the same name exist in both tables.