Question

如何从昨天开始只选择我的sql数据库？这是我的代码：

      SELECT *, COUNT(visitors.usr_id) as usr_count FROM user, visitors WHERE visitors.usr_id = $usr_id GROUP BY $usr_id ORDER BY usr_count LIMIT 1

我的数据库名称是timein以及它输入INSERT完成日期和时间的方式。这是代码：

      Database column :    timein

      Database insert looks like :    2012-9-6 9:11:35

基本上我希望能够从昨天开始SELECT和COUNT。我怎样才能从昨天开始从我的sql数据库中选择COUNT？

Answer 1

您的查询没有意义。您正在user和visitors之间进行交叉联接，然后仅对访问者进行过滤。我怀疑你想要的东西：

SELECT *, COUNT(visitors.usr_id) as usr_count
FROM user join
     visitors
     on visitors.usr_id = user.usr_id
WHERE user.usr_id = $usr_id
GROUP BY $usr_id
ORDER BY usr_count
LIMIT 1;

获取昨天数据的where子句将是：

WHERE date(timein) = date(NOW() - INTERVAL 1 DAY)

或者，如果您在timein上有索引：

WHERE timein >= date(NOW() - INTERVAL 1 DAY) and timein < date(NOW())

Answer 2

试试这个为昨天添加条件timein <= NOW() - INTERVAL 1 DAY , timein >= NOW() - INTERVAL 2 DAY;

SELECT *, COUNT(visitors.usr_id) as usr_count 
FROM user, visitors 
WHERE visitors.usr_id = $usr_id
AND timein <= NOW() - INTERVAL 1 DAY
AND timein >= NOW() - INTERVAL 2 DAY
GROUP BY $usr_id 
ORDER BY usr_count
LIMIT 1

或者您可以使用BETWEEN

SELECT *, COUNT(visitors.usr_id) as usr_count 
FROM user, visitors 
WHERE visitors.usr_id = $usr_id
AND timein BETWEEN  NOW() - INTERVAL 1 DAY AND  NOW() - INTERVAL 2 DAY;
GROUP BY $usr_id 
ORDER BY usr_count
LIMIT 1

从昨天开始从数据库中选择sql

2 个答案: