how to count datas according to condition in mysql?

Question

0.00/5 (No votes)

See more:

hi friends
I want to describe my problem there is a database table these table has some column I wanto to count datas...

id lesson Z K
1 x 0 0
2 x 0 0
3 x 2 1
4 x 2 1

only I will count when Z column has zero so this result will be 2
select count(x) from table where z=0 this result has 2

but when K column value is 1 I will add 2 datas so result will be 4

there is a condition here normally sql will count if z=0 so result 2
if k=1 sql count all of them so result will be 4

conditional count
how should be mysql query string?
thanks a lot.

Posted 5-Apr-13 1:46am

Member-2338430

Updated 5-Apr-13 1:49am

v2

Add a Solution

Comments

kishore sharma 5-Apr-13 8:11am

"when K column value is 1 I will add 2 datas so result will be 4"
what is the condition in query you want to check in this condition?

CPallini 5-Apr-13 8:20am

You should state more clearly what you are trying to accomplish, in my opinion.

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Maciej Los · Answer 1 · 2013-04-05T03:00:00

It should works:

SQL

SELECT SUM(CountMyCol) AS SumOfZK
FROM(
    (SELECT COUNT(x) CountMyCol
    FROM MyTable
    WHERE z=0)
    UNION ALL
    (SELECT COUNT(x) CountMyCol
    FROM MyTable
    WHERE k=1))

More:
http://dev.mysql.com/doc/refman/5.0/en/union.html[^]
http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html[^]