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SQL SUM Command
Let us learn about the SUM sql command and how to use it in our tables. SUM
command can be applied to numeric field and the total of the value is returned.
Now let us apply this SUM command to this table and find out the total mark
obtain by all the students. The SUM command will add all the values of the mark
field and return to us. This is our table
| id |
name |
class |
mark |
| 1 |
John Deo |
Four |
75 |
| 2 |
Max Ruin |
Three |
85 |
| 3 |
Arnold |
Three |
55 |
| 4 |
Krish Star |
Four |
60 |
| 5 |
John Mike |
Four |
60 |
| 6 |
Alex John |
Four |
55 |
We will apply the SUM command here like this to the field mark
SELECT sum( mark ) FROM `student`
The command added all the values of the mark field and displayed. We can define
some header like this also.
SELECT SUM(mark) as total_mark FROM `student`
Now let us find out what is the total mark in each class. Here we can use the Group
By command to find out the total mark obtained by each class
SELECT class, sum( mark ) as total_mark FROM`student` GROUP BY class
| class | total_mark |
|---|
| Four | 250 |
| Three | 140 |
You can see above that total mark of each class is displayed. Since we have two
class in our table so the sql command has returned two class with total marks in
each of them. We have to use Group
By clause if we ask for the query to return any other field name other than
the sum. Otherwise system will generate error.
We can add condition to the sql command to get our desired result. We can add
one Where clause to the query to consider records
for which mark is more than some value ( say 55 )
SELECT sum( mark ) as total_mark, class FROM student where mark > 55 GROUP BY class
| total_mark |
class |
| 195 |
Four |
| 85 |
Three |
Other sql commands like between can be used along with this sum command to
find out required results.
Learn how to use SQL sum in multiple columns
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