MySQL查询，多列求和

Question

I have multiple columns in a mySQL table. Three of the columns are named i100s, i60s and i25s and what I want to do is get the sum of all three entries . currently I have this code

   '$query= "SELECT SUM(i100s),SUM(i60s),SUM(i25s) AS tkit FROM event WHERE acc='100' " ; 
    $result = mysql_query($query) or die(mysql_error());
    $row = mysql_fetch_assoc($result) ;
    $total =  $row['tkit'];' 

But it is not returning the correct result.

Answer 1

Combined sum of all three columns?

If so, simply add them up:

'$query= "SELECT SUM(i100s) + SUM(i60s) + SUM(i25s) AS tkit FROM event WHERE acc='100' " ;

Answer 2

SELECT (SUM(i100s) + SUM(i60s) + SUM(i25s)) AS tkit ...

这将返回列总和。

Answer 3

There will be different methods.... and the payments are payed on method_1, method_2, method_3. So I want to calculate the sum of one particular method say 1000.. for all method types.

Table: payment_test

id method_1 payment_1 method_2 payment_2 method_3 payment_3
1  1000     100       1001     200       1001     100
2  1011     100       1000     100       1000     100
3  1010     200       1001     100       1010     200
4  1000     400       1010     500       1001     100


SELECT SUM(
    CASE WHEN method_1 ='1000' THEN payment_1 ELSE 0 END
    + CASE WHEN method_2 ='1000' THEN payment_2 ELSE 0 END
    + CASE WHEN method_3 ='1000' THEN payment_3 ELSE 0 END) as payment
FROM payment_test

Output:

payment
700