Because of its prevalence in the business world, more and more people are looking for ways to learn MySQL. The software has many commands and features, so it will take time to master it. However, the following information will give you an idea of how the software works.
How to Use UPDATE in a MySQL Query
The UPDATE command is used to alter columns present in the database. This is useful for updating information.
To add data, use the INSERT command. To make updates, there must be a row to alter. The row should have its own ID referring to it. Ensure each table ID is unique.
You can do this by using the INTEGER AUTO_INCREMENT column. If utilizing an ID field, the field won’t be in the INSERT command. The AUTO_INCREMENT attribute will be used.
INSERT INTO customers name,ph_number,balance VALUES (“Jane Doe”,”555-5555″,0.0);
Note: when studying ways to learn MySQL, the names you enter should be changed to the ones that are appropriate for your case.
The SELECT query can be used to locate data. The old balance must be retrieved to make an update to it. As you are just focusing on the ID number and balance, these are the only columns that have to be pulled. Example:
SELECT id,balance FROM customers WHERE name=’Jane Doe’ AND ph_number=”555-5555″;
Do the UPDATE MySQL Query with the UPDATE command. The command actually looks a bit like SELECT and INSERT. The following assumes the ID and balance have been retrieved from the preceding query.
UPDATE customers SET balance=12.34 WHERE id=22;
Tips and Warnings
Take care not to commit errors with the WHERE clause. Used incorrectly you may end up updating other rows too. If you updated the present query rather than the preceding one, all customers named Jane Doe will have their balance updated. For instance:
UPDATE customers SET balance=12.34 WHERE name=”Jane Doe”;
It is very practical to have different IDs for all the rows. It goes a long way towards making data retrieval easier especially with the SELECT query. The ID field from the earlier query ought to be saved. This will ensure the query being updated is the correct one.
It may take some time before you master the features of MySQL. But since there are many ways to learn MySQL, grasping the basic commands will be easy. From there, you will be able to move on to more complex features.