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Update the table by calculating the sum and display the result as last column value
Use a variable to store SUM(total) and update it with the UPDATE command. Let us first create a table −
mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Value int ); Query OK, 0 rows affected (0.61 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable(Value) values(70); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(Value) values(100); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Value) values(150); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Value) values(250); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(Value) values(60); Query OK, 1 row affected (0.22 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+----+-------+ | Id | Value | +----+-------+ | 1 | 70 | | 2 | 100 | | 3 | 150 | | 4 | 250 | | 5 | 60 | +----+-------+ 5 rows in set (0.00 sec)
Following is the query to set the sum in a variable and display the result as last column value −
mysql> set @Total=(select sum(Value) from DemoTable); Query OK, 0 rows affected (0.00 sec) mysql> update DemoTable set Value= @Total where Id=5; Query OK, 1 row affected (0.16 sec) Rows matched: 1 Changed: 1 Warnings: 0
Let us check the table records once again −
mysql> select *from DemoTable;
This will produce the following output −
+----+-------+ | Id | Value | +----+-------+ | 1 | 70 | | 2 | 100 | | 3 | 150 | | 4 | 250 | | 5 | 630 | +----+-------+ 5 rows in set (0.00 sec)
Updated on: 04-Oct-2019
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