MySQL HAVING& WHERE查询不同的结果

时间:2014-05-14 09:59:53

标签: mysql having

我只是一个MySQL初学者。这是第一次让我们在STACKOVERFLOW上询问有关使用HAVING和WHERE的查询:

SELECT 
    BOXNUMBER
    ,COUNT(BOXNUMBER) AS QTY
    ,CDATETIME 
FROM 
    HSS_SNO 
WHERE 
    year(CDATETIME) IN ('2008','2010','2014') 
GROUP BY 
    BOXNUMBER ;

/* Affected rows: 0  Found rows: 13,928  Warnings: 0  Duration for 1 query: 0.031 sec. (+ 2.782 sec. network) */

SELECT 
    BOXNUMBER
    ,COUNT(BOXNUMBER) AS QTY
    ,CDATETIME 
FROM 
    HSS_SNO 
GROUP BY 
    BOXNUMBER 
HAVING 
    year(CDATETIME) IN ('2008','2010','2014');

 /* Affected rows: 0  Found rows: 13,922  Warnings: 0  Duration for 1 query: 0.047 sec. (+ 2.594 sec. network) */

我认为这些查询会给我相同的结果,但“找到的行”彼此不同。 你能告诉我为什么这样吗?

由于 托宾 (抱歉我的英文)

0 个答案:

没有答案