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42 lines
1.3 KiB
Markdown
42 lines
1.3 KiB
Markdown
# DELETE
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As the name suggests, the `DELETE` statement would remove data from your database.
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The syntax is as follows:
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```sql
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DELETE FROM users WHERE id=5;
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```
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The output should indicate that 1 row was affected:
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```
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Query OK, 1 row affected (0.01 sec)
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```
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> Important: Just like the `UPDATE` statement, if you don't specify a `WHERE` clause, all of the entries from the table will be affected, meaning that all of your users will be deleted. So, it is critical to always add a `WHERE` clause when executing a `DELETE` statement.
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```sql
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DELETE FROM users;
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```
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The output should indicate (where x is the number of tuples in the table):
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```
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Query OK, x row(s) affected (0.047 sec)
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```
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Similar to the Linux `rm` command, when you use the `DELETE` statement, the data would be gone permanently, and the only way to recover your data would be by restoring a backup.
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## Delete from another table
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As we saw in the two precedents sections you can `INSERT` or `UPDPATE` tables rows based on other table data. You can do the same for the `DELETE`.
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For example, if you want to delete the records from the `users` table if the corresponding prospect has been disabled, you could do it this way:
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```sql
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delete users
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from users, prospect_users
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where users.username = prospect_users.username
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and NOT prospect_users.active
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```
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