如何使用数据库检索空值

本文介绍了如何使用数据库检索空值的处理方法，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

我有两列，一个是值，第二个是null，我想检索两列的数据，请使用where where help

解决方案

你可以试试

SELECT * FROM myTable WHERE myTable.A = value OR myTable.B为null

另一种方法是

SELECT * FROM myTable WHERE myTable.A = value UNION SELECT * FROM myTable WHERE myTable.B为null

i have two columns one is having values and second one is null and i want to retrieve data for both columns using where condition please help

解决方案

You can try

SELECT * FROM myTable WHERE myTable.A = value OR myTable.B is null

An alternate approach is

SELECT * FROM myTable WHERE myTable.A = value UNION SELECT * FROM myTable WHERE myTable.B is null