Question

我有三张桌子：

客户： ID，名称
contracts_jewels ： id，customer_id，paid，transferred，final_date
contracts_objects ： id，customer_id，paid，transferred，final_date

如您所见，最后两个表的结构是相同的。＆＃34; 付费＆＃34;并且＆＃34; 已转移＆＃34;字段包含值0或1。

我需要的是创建一个应该返回所有客户端的查询（无论是否有合同），以及每个客户端： id，name， count_contracts_all ， count_contracts_active

其中：

count_contracts_all 表示[SELECT COUNT（*）FROM的总和 contracts_jewels WHERE customer_id = 3（例如）]和[SELECT COUNT（*）FROM contracts_objects WHERE customer_id = 3（例如）]
count_contracts_active 表示[SELECT COUNT（*）FROM的总和 contracts_jewels WHERE customer_id = 3 AND final_date＆gt; = Now（）AND paid = 0 AND transferred = 0]和[SELECT COUNT（*）FROM contracts_objects WHERE customer_id = 3 AND final_date＆gt; = Now（）AND paid = 0 AND transferred = 0]

有什么想法吗？你能帮帮我吗？谢谢！

Answer 1

我现在能想到的一个快速解决方案是：

SELECT COUNT(`temp_table`.*) FROM (
    SELECT * FROM contracts_jewels WHERE customer_id=3 UNION ALL
    SELECT * FROM contracts_objects WHERE customer_id=3) AS `temp_table`

和

SELECT COUNT(`temp_table`.*) FROM (
SELECT * FROM contracts_jewels WHERE customer_id=3 AND final_date>=Now() AND paid=0 AND transferred=0 UNION ALL
    SELECT * FROM contracts_objects WHERE customer_id=3 AND final_date>=Now() AND paid=0 AND transferred=0)  AS `temp_table`

Answer 2

您可以单独计算合约，然后将它们加入客户：

SELECT
    c.id,
    COALESCE(oc.active_count,0) + COALESCE(jc.active_count,0) as count_contracts_active,
    COALESCE(oc.total_count,0) + COALESCE(jc.total_count,0) as count_contracts_all
FROM customers c
LEFT JOIN (
    SELECT
        customer_id
        COUNT(*) as total_count,
        COUNT(IF(final_date>=Now() AND paid=0 AND transferred=0,1,NULL)) as active_count
    FROM contracts_jewels
    GROUP BY customer_id
) as oc ON oc.customer_id = c.id
LEFT JOIN (
    SELECT
        customer_id
        COUNT(*) as total_count,
        COUNT(IF(final_date>=Now() AND paid=0 AND transferred=0,1,NULL)) as active_count
    FROM contracts_objects
    GROUP BY customer_id
) as jc ON jc.customer_id = c.id

Answer 3

您可以将每个表格加入两次，并在结果中添加相应的TelecomManager telecomManager = (TelecomManager) getSystemService(Context.TELECOM_SERVICE); ComponentName componentName = newComponentName("se.example.connectionservicestandalonetest", "se.example.connectionservicestandalonetest.MyConnectionService"); PhoneAccountHandle phoneAccountHandle = new PhoneAccountHandle(componentName, "Admin"); PhoneAccount phoneAccount = PhoneAccount.builder(phoneAccountHandle, "Admin").build(); telecomManager.registerPhoneAccount(phoneAccount);：

COUNT

注意：我没有运行它，但希望它能让你朝着正确的方向前进。

Answer 4

简单的解决方案：

SELECT SUM(c) FROM (
    SELECT COUNT(1) as c FROM `tbl1` where ...
UNION
    SELECT COUNT(1) as c FROM tbl2 where ...
UNION
    SELECT COUNT(1) as c FROM tbl3 where ...
) al

MySQL查询 - 来自多个表的COUNT的SUM

4 个答案: