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Update column data without using temporary tables in MySQL?


1 Answer
Sharon Christine

For this, use CASE statement. This will work even without using temporary tables. Let us first create a table −

mysql> create table DemoTable
   -> (
   -> UserName varchar(100),
   -> UserStatus varchar(100)
   -> );
Query OK, 0 rows affected (0.74 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('John','Active');
Query OK, 1 row affected (0.29 sec)

mysql> insert into DemoTable values('Chris','Inactive');
Query OK, 1 row affected (0.19 sec)

mysql> insert into DemoTable values('Bob','Inactive');
Query OK, 1 row affected (0.32 sec)

mysql> insert into DemoTable values('Robert','Active');
Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+----------+------------+
| UserName | UserStatus |
+----------+------------+
| John     | Active     |
| Chris    | Inactive   |
| Bob      | Inactive   |
| Robert   | Active     |
+----------+------------+
4 rows in set (0.00 sec)

Following is the query to update column data using CASE −

mysql> update DemoTable
   -> set UserStatus=CASE UserStatus WHEN 'Inactive' THEN 'Active' ELSE 'Inactive' END;
Query OK, 4 rows affected (0.28 sec)
Rows matched: 4 Changed: 4 Warnings: 0

Let us check table records once again −

mysql> select *from DemoTable;

This will produce the following output −

+----------+------------+
| UserName | UserStatus |
+----------+------------+
| John     | Inactive   |
| Chris    | Active     |
| Bob      | Active     |
| Robert   | Inactive   |
+----------+------------+
4 rows in set (0.00 sec)

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