SQL对照另一个检查一个列表 [英] SQL Check one list against Another

问题描述

对于使用SQL如何检查一个列表中的元素是否也出现在另一个列表中的任何指示，我将不胜感激.

I'd appreciate any pointers on how in SQL to check whether elements in one list also appear in another.

List A = Live Customers in April
List B = Live Customers in May

如何检查列表A中的哪些客户也出现在列表B中?识别丢失的客户

How can I check which Customers in List A also appear in List B ? to identify those Customers which have been lost

i.e. Customers in A but not in B.

感谢您的帮助. Gav

Thank you for your help. Gav

推荐答案

提取结果的不同方法

SELECT customer
FROM ListA a 
WHERE NOT EXISTS (SELECT 1 FROM ListB b WHERE a.customer=b.customer)

OR

SELECT a.customer
FROM ListA a 
  LEFT JOIN ListB b ON a.customer=b.customer
WHERE b.customer is null

OR

SELECT customer
FROM ListA

except

SELECT customer
FROM ListB

OR

SELECT customer
FROM ListA 
WHERE customer NOT IN (SELECT customer FROM ListB )

这篇关于SQL对照另一个检查一个列表的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！