PHP mysqli Select Add field

Question

I have a table that looks like this:

id | user_id | credits
----------------------
1  | 2       | 300
2  | 2       | 200
3  | 4       | 100

I need a select or way to add the credits from a specific user id

The select would be:

SELECT credit FROM myTable WHERE user_id ='2'

The result I would need in this case would be 500

How can I do this?

This is a pretty trivial question. Quick googling for "mysql sum column" would have saved you some time and yielded useful results. — Dzhuneyt, Feb 19 '15 at 11:21
possible duplicate of [MySql sum elements of a column](http://stackoverflow.com/questions/4586040/mysql-sum-elements-of-a-column) — Dzhuneyt, Feb 19 '15 at 11:23

Gunaseelan · Accepted Answer · 2015-02-19T11:42:47.047

Use SUM() in your query will solve the issue.

SELECT SUM(`credits`) AS `total` FROM `myTable` WHERE `user_id` =2

Since you specify PHP tag, the below code will help you.

$mysqli=mysqli_connect("hostname","username","password","databasename");
$query = "SELECT SUM(`credits`) AS `total` FROM `myTable` WHERE `user_id` =2";
$processquery = $mysqli->query($query);
$result = $processquery->fetch_assoc();
echo $result['total'];

score 1 · Answer 2 · answered Feb 19 '15 at 11:13

1

Use sum()

SELECT sum(credit) as sum_credit
FROM myTable
WHERE user_id = 2

answered Feb 19 '15 at 11:13

juergen d

201,996
37
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362

score 1 · Answer 3 · answered Feb 19 '15 at 11:13

1

Use aggregate function SUM():

SELECT SUM(credit) as TotalCredit
FROM myTable 
WHERE user_id='2'

Read more about aggregate functions here.

answered Feb 19 '15 at 11:13

Raging Bull

18,593
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Styphon · Answer 4 · 2015-02-19T11:20:14.150

You can do this by summing the total of the credit column. Check out the MySQL reference manual for the official instructions.

SELECT SUM(credit) AS credit_total
FROM myTable
WHERE user_id = 2

You use the AS keyword to assign a name to your column, then in PHP you can access this column as you would any other by name, just using credit_total. E.g:

$query = "SELECT SUM(credit) AS credit_total
    FROM myTable
    WHERE user_id = 2";
$result = $mysqli->query($query);
$row = $result->fetch_assoc();
echo $row['credit_total']; // Will output 500

score 1 · Answer 5 · answered Feb 19 '15 at 11:14

1

Try SUM() in mysql

SELECT SUM(credit) as totalcredit FROM myTable WHERE user_id ='2'

will return you matched result sum according to condition

answered Feb 19 '15 at 11:14

Rakesh Sharma

13,680
5
37
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score 1 · Answer 6 · answered Feb 19 '15 at 11:15

1

select sum(credit) as total from myTable where user_id = '2'

answered Feb 19 '15 at 11:15

Shailesh Katarmal

2,757
1
12
15

PHP mysqli Select Add field

6 Answers6