Difference between 2 selects in SQL
I have one data table:
--------------------
ID | user | Value
--------------------
1 | 1 | 1
--------------------
2 | 1 | 2
--------------------
3 | 2 | 3
--------------------
4 | 2 | 2
--------------------
5 | 3 | 4
--------------------
6 | 3 | 2
--------------------
I would like to SELECT all rows where value is different comparing to user 1 so the result would be rows with IDs 3 (value is 3) and 5 (value is 2)
I would do something like this (will call it A)
开发者_开发知识库SELECT * FROM table WHERE user = 1
and get all the rows from user 1. Than I would select (will call it B)
SELECT * FROM table WHERE user != 1
and get all other rows. And than I would compare them WHERE A.value != B.value
.
I'm stuck on how to merge everything together...
Please help!
Try this:
SELECT *
FROM table
WHERE value NOT IN ( SELECT value FROM table WHERE user = 1)
The relational operator is indeed 'difference', Oracle has the keyword MINUS
, Standard SQL has the keyword EXCEPT
e.g.
SELECT value
FROM table
EXCEPT
SELECT value
FROM table
WHERE user = 1;
Sadly, MySQL doesn't have any such an operator, you have to use other SQL constructs e.g. NOT IN <table expression>
:
SELECT value
FROM table
WHERE value NOT IN ( SELECT value
FROM table
WHERE user = 1 );
select * from table where value not in (select value from table where user = 1);
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