SQL查询：没有选择行

我尝试了sql语句的不同变体，但我仍然在选择“没有行”。我不知道我要去哪里错了！SQL查询：没有选择行

这里有一个问题：

我必须列出了其经理是“绿色”的员工举办的会议的标题。

与查询相关联的表是：

Employee_C表：

EID NAME SALARY   MID 
--- -------------------- ----- 
e01 Wilson 53000 
e02 Smith  48000  e01 
e03 Jones  38000  e01 
e04 Loftus  41000 
e05 Fox  54000  e04 
e06 Smith  45000  e04 
e07 Green  48000 
e08 Fox  49000  e04 
e09 Wolf  41000  e04 
e10 Wang  32000  e01 
e11 Phillips 33000  e07 
e12 Liu   27000  e07

Conference_C表：

CONFID    TITLE      LOCATION   SDATE 
------  --------------------  -------------------- --------- 
c00001 Hydroinformatics     Singapore   15-JUN-12 
c00002 Ecological_modeling    Berlin    15-JUL-12 
c00003 Computational_M     London    25-MAY-12 
c00004 Ecoinformatics     Boston    22-AUG-12 
c00005 Uncertainty_analysis    Athens    10-OCT-12 
c00006 Large_databases     Toronto   13-APR-12 
c00007 Systems_analysis     Boston    23-MAR-12 
c00008 Systems_integration    Tokyo    24-FEB-12 
c00009 Aquatic_biology     Helsinki   12-MAY-12 
c00010 Information_systems    Paris    08-JAN-12 
c00011 Simulation_modeling    Rome    01-SEP-12 
c00012 DSS        Melbourne   18-DEC-12

Deals_C表：

EID CONFID 
--- ------ 
e02 c00001 
e03 c00001 
e05 c00001 
e06 c00001 
e03 c00002 
e08 c00002 
e09 c00002 
e10 c00002 
e03 c00003 
e05 c00003 
e06 c00004 
e08 c00005 
e09 c00005 
e10 c00005 
e06 c00005 
e11 c00006 
e12 c00006 
e05 c00007 
e06 c00007 
e08 c00007 
e09 c00008 
e10 c00008 
e11 c00008 
e02 c00009 
e12 c00009 
e10 c00010 
e02 c00011 
e03 c00011 
e05 c00011 
e12 c00012 
e06 c00012

的SQL语句，我有是：

select C.Title 
from Conference_C C 
where C.ConfID in (select D.ConfID 
        from Deals_C D 
        where D.eid in (select E.eid 
            from Employee_C E 
            where E.Name = 'Green'));

我“没有选择行”

来源

2013-03-26 Navy

您没有并且处理eid = 07。 – Mat 2013-03-26 18:54:51

Green的EID为e07，您在Deals_C表中没有任何含e07 EID的行。 – 2013-03-26 18:55:35

检查我的答案为什么它没有返回记录 – 2013-03-26 18:59:52

与您查询的问题是要检查错误的员工数据。你WHERE子句检查EID到EID当它真正应该检查Deals_C.EID到Employees.MID：

select C.Title 
from Conference_C C 
inner join 
(
    select D.ConfID, e.eid 
    from Deals_C D 
    inner join Employee_C e 
    on d.EID= e.EID 
    where exists (select * 
       from Employee_C e2 
       where E2.Name = 'Green' 
        and e.mid = e2.eid) 
) d 
    on c.CONFID = d.CONFID

见SQL Fiddle with Demo。

的EXISTS查询返回拥有的Green姓的行，但你需要检查Employee_C.MID的子查询EID。

这也可以写成：

select C.Title 
from Conference_C C 
where C.ConfID in (select D.ConfID 
        from Deals_C D 
        inner join Employee_C e 
        on d.EID= e.EID 
        where exists (select * 
           from Employee_C e2 
           where E2.Name = 'Green' 
            and e.mid = e2.eid));

见SQL Fiddle with Demo

来源

2013-03-26 19:03:24 Taryn

哦，没错！非常感谢您的帮助！ – Navy 2013-03-26 20:00:34

我只是有这个问题。我选择“没有选择行”的原因仅仅是因为我的sqlcase设置为UPPER，而我以小写查询。即WHERE empName LIKE'_a％'; 我将sqlcase设置为混合并解决了我的问题。看起来引号之间的字符串区分大小写。希望能帮助到你。

来源

2016-02-29 22:59:42 Loona

SQL查询：没有选择行

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