的MySQL从表中选择其中条件x和子查询

Question

我想表A登记的数量都在表B.确定的时间具体数额

我要找的正确的方式做一些像此：

SELECT count(*) as total 
from table_a as a 
WHERE a.created >= '0000-00-00 00:00:00' 
AND a.created <= (SELECT table_b.end WHERE table_b.id = 13) 

基本上，表-B由3米栏：命名的“id”的int主键，一个名为“开始”的日期时间，并命名为“结束”的其他日期时间。这是我确定今年所有周的方式。

Answer 1

以防万一有人需要的是，这是做的正确方法即：

SELECT count(*) as total 
from table_a as a 
WHERE a.created >= '0000-00-00 00:00:00' 
AND a.created <= (SELECT table_b.`end` FROM table_b WHERE table_b.`id`=13) 

Answer 2

SELECT count(*) as total 
from table_a as a 
WHERE a.created >= '0000-00-00 00:00:00' 
AND a.created <= (SELECT table_b.end from table_b WHERE table_b.id = 13) 

Answer 3

你可以做典型的联接：

SELECT COUNT(*) AS total 
FROM table_a AS a 
JOIN table_b as b ON (a.created >= '0000-00-00 00:00:00' and a.created <= b.`end`) 
WHERE b.id=13; 

鉴于你可能想要做的说明：

SELECT COUNT(*) AS total 
FROM table_a AS a 
JOIN table_b as b ON (a.created >= `start` and a.created <= `end`) 
WHERE b.id=13; 

Answer 4

你可以使用BETWEEN子句来实现这一点，

SELECT count(*) as total 
from table_a a 
WHERE a.created BETWEEN '0000-00-00 00:00:00' 
AND (SELECT table_b.`end` FROM table_b WHERE table_b.`id`=13)