什么是这个MySQL加入查询

Question

我有一个休息和clock_in_out表，我想从两者获取所有值，并将其加入到他们的user_id列中。但我越来越不正确synatx使用JOIN附近ON，不知道为什么。这里是我的查询

SELECT * 
FROM `breaks` 
WHERE `user_id` = 1 
AND `in_date` LIKE '%2015-03-03%' 
AND `out_date` LIKE '%2015-03-03%' 
JOIN `clock_in_out` ON `breaks`.`user_id` = `clock_in_out`.`user_id` 
WHERE `loggedin_date` 
LIKE '%2015-03-03%' 
AND `loggedout_date` LIKE '%2015-03-03%' 

Answer 1

您不能混用WHERE和JOIN这样的子句。订单是：SELECT,FROM,JOIN,WHERE,GROUP BY,HAVING,LIMIT。因此它应该是：

SELECT * 
FROM `breaks` 
JOIN `clock_in_out` ON `breaks`.`user_id` = `clock_in_out`.`user_id` 
WHERE `user_id` = 1 
AND `in_date` LIKE '%2015-03-03%' 
AND `out_date` LIKE '%2015-03-03%' 
AND `loggedin_date` LIKE '%2015-03-03%' 
AND `loggedout_date` LIKE '%2015-03-03%' 

有关完整的语法，请参阅MySQL documentation。

Answer 2

WHERE条款应JOIN后：

SELECT * 
FROM `breaks` JOIN 
    `clock_in_out` ON `breaks`.`user_id` = `clock_in_out`.`user_id` 
WHERE `user_id` = 1 
    AND `in_date` LIKE '%2015-03-03%' 
    AND `out_date` LIKE '%2015-03-03%' 
    AND `loggedin_date` LIKE '%2015-03-03%' 
    AND `loggedout_date` LIKE '%2015-03-03%' 

Answer 3

您的语法错误。对于加入正确的语法是Select ... from .. join ... on ... where

SELECT * 
FROM `breaks` 
JOIN `clock_in_out` ON `breaks`.`user_id` = `clock_in_out`.`user_id` 
WHERE `loggedin_date` 
LIKE '%2015-03-03%' 
AND `loggedout_date` LIKE '%2015-03-03%' 
AND `user_id` = 1 
AND `in_date` LIKE '%2015-03-03%' 
AND `out_date` LIKE '%2015-03-03%' 

Answer 4

对于这个正确的语法如下

SELECT * 
FROM `breaks` 
JOIN `clock_in_out` ON `breaks`.`user_id` = `clock_in_out`.`user_id` 
WHERE `user_id` = 1 
AND `in_date` LIKE '%2015-03-03%' 
AND `out_date` LIKE '%2015-03-03%' 
AND `loggedin_date` LIKE '%2015-03-03%' 
AND `loggedout_date` LIKE '%2015-03-03%