PHP/SQL : If statement within the query? - php

Question

Hi I am trying to create something but I can't have my total number being a negative. So basically I got values that are negative that can be multiplied into a somewhat complex mathematics equation.
So essentially... user inputs a data from -1 to 1. (-1, 0, 1)
And it get's multiplied into my formula. So my SQL query looks like this... (this part works!)
SELECT *, a, b, c AS TOTALNUMBER FROM MATH
ORDER BY TOTALNUMBER DESC
However, I need the total number to always be positive. So I have been trying for the past few hours to figure this out. I am sort of new to php/sql.
I am trying to include something like...
if (TOTALNUMBER < 0 ) {
TOTALNUMBER * -1.0
}
However I have no idea where to include this in the query or how to write it properly.
To clarify and update what I am looking for...
User can input -1,0,1
Data for A, B, C is for example. 10, 15, 20
User inputs: 1, -1, 0
A total = 10
B total = -15
C total = 0
Total ABC = -5
However, I need total to be 5 instead of -5 without changing any A, B, C values.

Answer 1

use like this
SELECT *, a, b, ABS(c) AS TOTALNUMBER FROM MATH
ORDER BY TOTALNUMBER DESC

Answer 2

IF(expr1,expr2,expr3)
If expr1 is TRUE (expr1 <> 0 and expr1 <> NULL) then IF() returns expr2; otherwise it returns expr3. IF() returns a numeric or string value, depending on the context in which it is used.
SELECT a, b, c, If (c <0 , c * -1, c) AS TOTALNUMBER FROM MATH
ORDER BY TOTALNUMBER DESC;
If you want the sum of all the fields to be your total number, assuming you have an id field:
SELECT a,b,c,ABS((sum(a)+(b)+(c))) AS TOTALNUMBER FROM MATH
group by mathid ORDER BY TOTALNUMBER DESC;
Here is an example:
mysql> select * from math;
+--------+----------+
| idmath | mathcol1 |
+--------+----------+
| 1 | 1 |
| 2 | 3 |
| 3 | -1 |
| 4 | -3 |
+--------+----------+
4 rows in set (0.00 sec)
mysql> SELECT idmath, If (mathcol1 <0 , mathcol1 * -1, mathcol1) AS TOTALNUMBER
FROM MATH ORDER BY TOTALNUMBER DESC;
+--------+-------------+
| idmath | TOTALNUMBER |
+--------+-------------+
| 2 | 3 |
| 4 | 3 |
| 1 | 1 |
| 3 | 1 |
+--------+-------------+
4 rows in set (0.00 sec)
mysql> SELECT idmath, mathcol1, If (mathcol1 <0 , mathcol1 * -1, mathcol1) AS TO
TALNUMBER FROM MATH ORDER BY TOTALNUMBER DESC;
+--------+----------+-------------+
| idmath | mathcol1 | TOTALNUMBER |
+--------+----------+-------------+
| 2 | 3 | 3 |
| 4 | -3 | 3 |
| 1 | 1 | 1 |
| 3 | -1 | 1 |
+--------+----------+-------------+
4 rows in set (0.00 sec)
mysql> SELECT mathcol1,mathcol2,mathcol3, (sum(ABS(mathcol1))+(mathcol2)+(mathco
l3)) AS TOTALNUMBER FROM MATH group by idmath ORDER BY TOTALNUMBER DESC;
+----------+----------+----------+-------------+
| mathcol1 | mathcol2 | mathcol3 | TOTALNUMBER |
+----------+----------+----------+-------------+
| 3 | 2 | 3 | 8 |
| -3 | 2 | 3 | 8 |
| -1 | 2 | 3 | 6 |
| 1 | 2 | 3 | 6 |
+----------+----------+----------+-------------+
4 rows in set (0.00 sec)
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