如何從表格中選擇值之間使用條件

我有一個表名稱用戶和一個列日期，我想從數據庫中使用日期condtion獲取值。

select sum(visitor) AS V FROM user WHERE date < '21-05-2012' AND dDateTime > '11-05-2012' 
select sum(visitor) AS c FROM user WHERE date < '21-06-2012' AND dDateTime > '11-06-2012' 
select sum(visitor) AS s FROM user WHERE date < '21-07-2012' AND dDateTime > '11-07-2012' 
select sum(visitor) AS g FROM user WHERE date < '21-08-2012' AND dDateTime > '11-08-2012'

我想在一個SQL語句這四個查詢

來源

2012-06-05 riz

你想要個結果1或4分的結果？ –

我正在使用這四個查詢我想在單個語句中進行這四個查詢 – riz

也許是這樣的：

select 
    sum(CASE WHEN date < '21-05-2012' AND dDateTime > '11-05-2012' THEN visitor ELSE 0 END) AS V, 
    sum(CASE WHEN date < '21-06-2012' AND dDateTime > '11-06-2012' THEN visitor ELSE 0 END) AS c, 
    sum(CASE WHEN date < '21-07-2012' AND dDateTime > '11-07-2012' THEN visitor ELSE 0 END) AS s, 
    sum(CASE WHEN date < '21-08-2012' AND dDateTime > '11-08-2012' THEN visitor ELSE 0 END) AS g 
FROM 
    user

來源

2012-06-05 07:23:41 Arion

如何從表格中選擇值之間使用條件

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