从MySQL数据库的两个表中获取行 [英] Getting Rows From Two Tables from mysql database

问题描述

大家好...
我有两张桌子，就像一张是

uid    name
1      peter
2      parker
3      jhon
4      watson
5      backinsale

还有另一个表:

uid    date
1      2011-11-26
2      2011-11-26

在这里，我需要获取第二个表中没有uid的记录，就像

uid    name
3      jhon
4      watson
5      backinsale 

我写了类似
的查询

 选择 * 来自 tbl1，tbl2 解决方案

尝试一下.

SELECT t2.uid, t2.name FROM t1
RIGHT JOIN t2 on t2.uid = t1.uid
WHERE t2.date IS NOT NULL

问候，
爱德华(Eduard)

尝试使用左加入 [ SELECT * FROM tbl1 左 JOIN tbl2 打开 tlb1.uid = tbl2.uid 位置 tbl2.uid = NUL L

OP指出结果为空，他说对了，该声明应为:

  SELECT  tbl1.uid，tbl1.name
 FROM  tbl1
左  JOIN  tbl2
打开 tbl1.uid = tbl2.uid
位置 tbl2.uid  IS   NULL  

我还更改了SELECT，否则还会显示tbl2的NULL列.

尝试如下查询.

 选择 * 来自表1 T1
其中 T1.uid 不是  in (选择 T2.uid 来自 Table2 T2); 

hi all...
i have two tables like one is

uid    name
1      peter
2      parker
3      jhon
4      watson
5      backinsale

and another table like:

uid    date
1      2011-11-26
2      2011-11-26

here i need to get records in which uid is not there in second table that is like

uid    name
3      jhon
4      watson
5      backinsale 

i written query like

select * from tbl1,tbl2 where tbl1.uid!=tbl2.uid

but it is not return correct result set
can any one help me please
thanks in advance...

解决方案

try this one.

SELECT t2.uid, t2.name FROM t1
RIGHT JOIN t2 on t2.uid = t1.uid
WHERE t2.date IS NOT NULL

Regards,
Eduard

Try using LEFT JOIN[^] like this:

SELECT *
FROM tbl1
LEFT JOIN tbl2
ON tlb1.uid = tbl2.uid
WHERE tbl2.uid = NULL

OP remarked that the result was empty and he is right the statement should be:

SELECT tbl1.uid, tbl1.name
FROM tbl1
LEFT JOIN tbl2
ON tbl1.uid = tbl2.uid
WHERE tbl2.uid IS NULL

I also changed the SELECT as otherwise the NULL columns of tbl2 are also shown.

Try as below Query.

Select * from Table1 T1
where T1.uid not in (Select T2.uid from Table2 T2);

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