Collections:
Use Existing Column Values in the SET Clause in MySQL
How To Use Existing Column Values in the SET Clause in MySQL?
✍: FYIcenter.com
If a row matches the WHERE clause in a UPDATE statement, existing values in this row can be used in expressions to provide new values in the SET clause. Existing values are represented by column names in the expressions. The tutorial exercise below shows a good example:
mysql> UPDATE fyi_links SET id = id+200, counts = id*2 WHERE id >= 500; Query OK, 5 rows affected (0.01 sec) Rows matched: 5 Changed: 5 Warnings: 0 mysql> SELECT id, url, notes, counts, DATE(created) FROM fyi_links WHERE id >= 500; +-----+-------------------+-------+--------+---------------+ | id | url | notes | counts | DATE(created) | +-----+-------------------+-------+--------+---------------+ | 801 | moc.retneciyf.ved | Wrong | 1602 | 2006-04-30 | | 802 | moc.retneciyf.abd | Wrong | 1604 | 2006-08-31 | | 803 | moc.retneciyf.aqs | Wrong | 1606 | 2006-08-31 | | 810 | | Wrong | 1620 | 2006-08-31 | | 700 | moc.retneciyf.www | Wrong | 1400 | 2006-08-31 | +-----+-------------------+-------+--------+---------------+ 5 rows in set (0.00 sec)
This statement increased values in the id column by 200. It also updated the counts column with the newly increased id value.
⇒ Order of Columns in the SET Clause in MySQL
⇐ Update Column Values on Multiple Rows in MySQL
2018-01-13, 1457🔥, 0💬
Popular Posts:
What Happens If the UPDATE Subquery Returns Multiple Rows in SQL Server? If a subquery is used in a ...
How To Use SQL*Plus Built-in Timers in Oracle? If you don't have a stopwatch/timer and want to measu...
How To Look at the Current SQL*Plus System Settings in Oracle? If you want to see the current values...
How to download and install the scaled-down database AdventureWorksLT in SQL Server? If you want to ...
How To Insert New Line Characters into Strings in SQL Server Transact-SQL? If you want to break a st...