Get the sum of multiple row (not all) values from a MySQL table?

You can use aggregate function SUM() from MySQL for this. Let us first create a table −

mysql> create table DemoTable
(
   Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   Amount int
);
Query OK, 0 rows affected (0.65 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable(Amount) values(400);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable(Amount) values(10);
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable(Amount) values(50);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable(Amount) values(500);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable(Amount) values(80);
Query OK, 1 row affected (0.09 sec)

Following is the query to display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+----+--------+
| Id | Amount |
+----+--------+
| 1  | 400    |
| 2  | 10     |
| 3  | 50     |
| 4  | 500    |
| 5  | 80     |
+----+--------+
5 rows in set (0.00 sec)

Here is the query to get the sum of rows (not all) out of MySQL table −

mysql> select sum(Amount) from DemoTable where Id in(1,4,5);

This will produce the following output −

+-------------+
| sum(Amount) |
+-------------+
| 980         |
+-------------+
1 row in set (0.00 sec)