mysql从表a中选择，其中条件x和子选择

我想将表A中的注册数量计算为表B中确定的特定时间量

我正在寻找这样做的正确方法：

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)

选择count（*）作为总计
从表a作为
其中a.created>=“0000-00-00:00:00”
和a.created
选择count（*）作为总计
从表a作为
其中a.created>=“0000-00-00:00:00”
a.created您可以执行典型的连接：

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;

选择COUNT（*）作为总计
从表a作为
将表b连接为（a.created>='0000-00-00 00:00:00'和a.created='start`和a.created，以防有人需要，这是正确的方法：

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)

选择count（*）作为总计
从表a作为
其中a.created>=“0000-00-00:00:00”
a.created您可以使用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)

您错过了第二个select查询中的From子句…谢谢！我没想到会如此接近解决方案！嗯，这是一种方法。不确定这是正确的方法！
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)

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)