Question

我正在使用以下查询：

$select_jan1 = "SELECT count(*) FROM users WHERE timeStamp BETWEEN '2015-01-01' and '2015-01-31'";
$select_feb1 = "SELECT count(*) FROM users WHERE timeStamp BETWEEN '2015-02-01' and '2015-02-28'";
$select_mar1 = "SELECT count(*) FROM users WHERE timeStamp BETWEEN '2015-03-01' and '2015-03-31'";

有没有办法将这3个查询放在一个？

谢谢

Answer 1

您可以使用条件聚合将值放在三列中：

SELECT SUM(timeStamp BETWEEN '2015-01-01' and '2015-01-31') as cnt_201501,
       SUM(timeStamp BETWEEN '2015-02-01' and '2015-02-28') as cnt_201502,
       SUM(timeStamp BETWEEN '2015-03-01' and '2015-03-31') as cnt_201503       
FROM users;

请注意，此逻辑会忽略每月最后一天的值。更好的逻辑是：

SELECT SUM(timeStamp >= '2015-01-01' and timestamp < '2015-02-01') as cnt_201501,
       SUM(timeStamp >= '2015-02-01' and timestamp < '2015-03-01') as cnt_201502,
       SUM(timeStamp >= '2015-03-01' and timestamp < '2015-04-01') as cnt_201503       
FROM users
WHERE timeStamp >= '2015-01-01' and timeStamp < '2015-04-01';

Answer 2

整整几个月，我这样做了：

SELECT
count(*)
FROM
(SELECT
year(timestamp) AS year_, month(timestamp) AS month_
FROM
users) s
WHERE
s.year_ = 2015 AND s.month_ >=4

减少不同时间间隔的mysql计数查询次数

2 个答案: