Question

此查询在where子句中给出了一个错误未知列公司。我发现where子句首先运行，然后选择运行。这可能是错误。但我不知道如何纠正这个问题，以便在结果集中得到公司。

SELECT trnsdriverid,
       name,
       (SELECT transcompany.name
        FROM   transcompany,
               transcompdriver
        WHERE  transcompany.trnscompid = transcompdriver.trnscompid) AS 'company',
       address,
       dob,
       license,
       telephone
FROM   transcompdriver
WHERE  ? LIKE 'All'
        OR name LIKE '%"+keyword+"%'
        OR company LIKE '%"+keyword+"%'
        OR trnsdriverid LIKE '%"+keyword+"%'

Answer 1

您无法在where语句中引用列别名。您应该重写此查询以使用JOIN，然后对实际的TransCompany.name列进行过滤，例如：

select 
     d.trnsDriverID
    ,d.name
    ,c.name as [Company]
    ,d.address
    ,d.dob
    ,d.license
    ,d.telephone 
from 
    TransCompDriver d
join
    TransCompany c
    on
    c.trnscompid = d.trnscompid
where 
    ? = 'All' 
    or 
    d.name like '%" + keyword + "%' 
    or 
    c.name like '%" + keyword + "%' 
    or 
    d.trnsDriverID like '%" + keyword + "%'

此外，不要使用简单等于运算符的LIKE。我将上面的查询更改为使用= 'All'。

Answer 2

你应该使用连接而不是子选择来做这件事。我会推荐这个：

SELECT
    d.trnsDriverID,
    d.name,
    c.name AS `company`,
    d.address,
    d.dob,
    d.license,
    d.telephone
FROM
    TransCompDriver AS d
    INNER JOIN TransCompany AS c
        ON d.trnsCompID = c.trnsCompID
WHERE
    ? like 'All'
    OR d.name LIKE '%"+keyword+"%'
    OR `company` LIKE '%"+keyword+"%'
    OR d.trnsDriverID LIKE '%"+keyword+"%'

Answer 3

拉取“公司”列的子查询没有匹配的行数，请尝试使用join语句

select trnsDriverID, name, t1.name AS company, address, dob, license, telephone    
from TransCompDriver JOIN (select trnsDriverID, name, 
(select TransCompany.name from TransCompany LEFT JOIN TransCompDriver   
ON TransCompany.trnsCompID=TransCompDriver.trnsCompID) AS t1   
where ? like 'All' or name like '%"+keyword+"%'   or company like '%"+keyword+"%' 
or trnsDriverID like '%"+keyword+"%'

MySQL在where子句之后执行select

3 个答案: