rewriting

landing/docs/SQL-101/010-delete.md

@@ -0,0 +1,50 @@
+# DELETE
+
+## Overview
+
+The `DELETE` statement is fundamental for data management, enabling the removal of rows  from a database table. Proper use ensures data integrity and efficiency within your application's data layer.
+
+## Basic DELETE
+
+Removes specific rows based on a condition. The `WHERE` clause is critical for precise targeting. Omitting it will affect  all rows in the table.
+
+```sql
+DELETE FROM users WHERE id=5;
+```
+
+A successful operation indicates the number of rows removed.
+
+```
+Query OK, 1 row affected (0.01 sec)
+```
+
+## Critical Warning
+
+Executing `DELETE` without a `WHERE` clause removes all data from the specified table.
+
+```sql
+DELETE FROM users;
+```
+
+Output reflects the total count of rows deleted.
+
+```
+Query OK, x row(s) affected (0.047 sec)
+```
+
+Unlike operations within a transaction that can be rolled back, standard `DELETE` operations are permanent. Recovery typically requires restoring from a backup.
+
+## Deleting Based on Related Tables
+
+Rows can be deleted from one table based on criteria evaluated against another table. This commonly involves using `JOIN` clauses within the `DELETE` statement to link related data. While the `FROM` clause may reference multiple tables, the `DELETE` clause specifies only the table from which rows are removed.
+
+For instance, to remove users from the `users` table if their corresponding entry  in `prospect_users` is marked inactive:
+
+```sql
+delete users
+from users, prospect_users
+where users.username = prospect_users.username
+and NOT prospect_users.active;
+```
+
+This approach efficiently removes dependent  data, maintaining data consistency across related tables.