mysql - 如何将两个具有不同列的查询合并为一个？

Question

如何将这两个查询合并到一张表中。它们是两个不同的结果，所以我需要它们是两个不同的列。我尝试过 UNION，但这将它们放入一列中。

SELECT COUNT(*) AS Number_Customers FROM customer
Where cus_balance > 0;
Select SUM(cus_balance) AS Total_Balances
FROM customer;

Answer 1

将它们重写为子查询，并使用 DUAL 作为虚拟表。

SELECT
   (SELECT COUNT(*) FROM customer WHERE cus_balance > 0) AS Number_Customers,
   (SELECT SUM(cus_balance) FROM customer) AS Total_Balances
FROM DUAL;

如果WHERE子句可能相同，那么你可以简单地这样写:

SELECT COUNT(*) AS Number_Customers,
       SUM(cus_balance) AS Total_Balances
FROM Cusomers
WHERE cus_balance > 0;