MySQL查询以获取列的和

我需要得到有两个条件的列的和，即

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

我需要编写查询，这样我就可以得到

dos      Total_amount selfpay

29/11/14 2400           1200

请引导我去哪里查询

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;

可能重复的