MySQL查询获取某列的

Question

我需要得到列的总和两个conditions.ie总和

例如：

Dos  Insurance bill_amount 
29/11/14 LIC  200 
29/11/14 Medicare  300 
29/11/14 Selfpay  300 
29/11/14 Medicare  400 
29/11/14 aetna  900 
29/11/14 selfpay  900 
29/11/14 Prestige  100 
29/11/14 LIC  500 

我需要写的查询，使我得到的观点作为

dos  Total_amount selfpay 

29/11/14 2400   1200 

请指引我WITE查询

Answer 1

试试这个：

SELECT Dos, 
     SUM(CASE WHEN Insurance != 'Selfpay' THEN bill_amount ELSE 0 END) Total_amount, 
     SUM(CASE WHEN Insurance = 'Selfpay' THEN bill_amount ELSE 0 END) selfpay 
FROM tableA 
GROUP BY Dos;