在连接表上搜索全名

Question

我已经写了一个查询来在连接表上按全名搜索，但是我得到这个错误。任何想法？

SELECT wrs.id, wrs.fname, wrs.sname, wrs.email1, wrs.applied, wrs.firstlogin, wrs.tel1, 
     SUBSTR(wrs.lastlogin, -10) AS last_login, 
     CONCAT_WS( ' ', wrs.fname, wrs.sname) AS full_name, wqs.level, 
     wqs.subject, wqs.university, wqs.dissertation 
FROM temp_users AS wrs 
    LEFT JOIN writer_qualifications AS wqs ON wqs.writer_id = wrs.id 
WHERE wrs.fname LIKE '%micky%' 
    OR wrs.sname LIKE '%micky%' 
    OR full_name LIKE '%micky%' 
    AND wrs.status = '1' 
GROUP BY wrs.id 


MySQL said: Documentation 

#1054 - Unknown column 'full_name' in 'where clause' 

Answer 1

不能使用别名，如WHERE子句中full_name，看到manual

标准SQL不允许在WHERE子句中的列别名引用。 此限制是因为在WHERE子句为 求值时，列值可能尚未确定。

所以你必须使用表达式CONCAT_WS( ' ', wrs.fname, wrs.sname)在WHERE子句中，而不是别名full_name的：

SELECT wrs.id, wrs.fname, wrs.sname, wrs.email1, wrs.applied, wrs.firstlogin, wrs.tel1, 
    SUBSTR(wrs.lastlogin, -10) AS last_login, 
    CONCAT_WS( ' ', wrs.fname, wrs.sname) AS full_name, wqs.level, 
    wqs.subject, wqs.university, wqs.dissertation 
FROM temp_users AS wrs 
    LEFT JOIN writer_qualifications AS wqs ON wqs.writer_id = wrs.id 
WHERE wrs.fname LIKE '%micky%' 
    OR wrs.sname LIKE '%micky%' 
    OR CONCAT_WS( ' ', wrs.fname, wrs.sname) LIKE '%micky%' 
    AND wrs.status = '1' 
GROUP BY wrs.id 

Answer 2

你不能在使用聚合（“FULL_NAME”）的别名WHERE子句，因为服务器通常在执行集合工作之前处理WHERE子句。这个问题/答案有很多选项和解释给你：Reference alias (calculated in SELECT) in WHERE clause