docs: delete from table as alias (#13568)

* Update dml-delete-from.md

* Update dml-delete-from.md

docs/doc/14-sql-commands/10-dml/dml-delete-from.md

@@ -4,7 +4,7 @@ title: DELETE
 
 import FunctionDescription from '@site/src/components/FunctionDescription';
 
-<FunctionDescription description="Introduced: v1.1.60"/>
+<FunctionDescription description="Introduced or updated: v1.2.174"/>
 
 Removes one or more rows from a table.
 
@@ -15,43 +15,36 @@ Databend ensures data integrity with atomic operations. Inserts, updates, replac
 ## Syntax
 
 ```sql
-DELETE FROM <table_name> [[AS] alias]
+DELETE FROM <table_name> [AS <table_alias>] 
 [WHERE <condition>]
 ```
+- `AS <table_alias>`: Allows you to set an alias for a table, making it easier to reference the table within a query. This helps simplify and shorten the SQL code, especially when dealing with complex queries involving multiple tables. See an example in [Deleting with subquery using EXISTS / NOT EXISTS clause](#deleting-with-subquery-using-exists--not-exists-clause).
 
-DELETE FROM does not support the USING clause yet. If you need to use a subquery to identify the rows to be removed, include it within the WHERE clause directly. See examples in [Subquery-Based Deletions](#subquery-based-deletions).
+- DELETE does not support the USING clause yet. If you need to use a subquery to identify the rows to be removed, include it within the WHERE clause directly. See examples in [Subquery-Based Deletions](#subquery-based-deletions).
 
 ## Examples
 
-### Direct Row Deletion
+### Example 1: Direct Row Deletion
+
+This example illustrates the use of the DELETE command to directly remove a book record with an ID of 103 from a "bookstore" table.
 
 ```sql
--- create a table
+-- Create a table and insert 5 book records
 CREATE TABLE bookstore (
   book_id INT,
   book_name VARCHAR
 );
 
--- insert values
 INSERT INTO bookstore VALUES (101, 'After the death of Don Juan');
 INSERT INTO bookstore VALUES (102, 'Grown ups');
 INSERT INTO bookstore VALUES (103, 'The long answer');
 INSERT INTO bookstore VALUES (104, 'Wartime friends');
 INSERT INTO bookstore VALUES (105, 'Deconstructed');
 
--- show the table before deletion
-SELECT * FROM bookstore;
-
-101|After the death of Don Juan
-102|Grown ups
-103|The long answer
-104|Wartime friends
-105|Deconstructed
-
--- delete a book (Id: 103)
+-- Delete a book (Id: 103)
 DELETE FROM bookstore WHERE book_id = 103;
 
--- show the table again after deletion
+-- Show all records after deletion
 SELECT * FROM bookstore;
 
 101|After the death of Don Juan
@@ -60,30 +53,35 @@ SELECT * FROM bookstore;
 105|Deconstructed
 ```
 
-### Subquery-Based Deletions
+### Example 2: Subquery-Based Deletions
 
 When using a subquery to identify the rows to be deleted, [Subquery Operators](../30-query-operators/subquery.md) and [Comparison Operators](../30-query-operators/comparisons/index.md) can be utilized to achieve the desired deletion.
 
 The examples in this section are based on the following two tables:
 
 ```sql
--- Table: employees
-+----+----------+------------+
-| id | name     | department |
-+----+----------+------------+
-| 1  | John     | HR         |
-| 2  | Mary     | Sales      |
-| 3  | David    | IT         |
-| 4  | Jessica  | Finance    |
-+----+----------+------------+
-
--- Table: departments
-+----+------------+
-| id | department |
-+----+------------+
-| 1  | Sales      |
-| 2  | IT         |
-+----+------------+
+-- Create the 'employees' table
+CREATE TABLE employees (
+  id INT,
+  name VARCHAR,
+  department VARCHAR
+);
+
+-- Insert values into the 'employees' table
+INSERT INTO employees VALUES (1, 'John', 'HR');
+INSERT INTO employees VALUES (2, 'Mary', 'Sales');
+INSERT INTO employees VALUES (3, 'David', 'IT');
+INSERT INTO employees VALUES (4, 'Jessica', 'Finance');
+
+-- Create the 'departments' table
+CREATE TABLE departments (
+  id INT,
+  department VARCHAR
+);
+
+-- Insert values into the 'departments' table
+INSERT INTO departments VALUES (1, 'Sales');
+INSERT INTO departments VALUES (2, 'IT');
 ```
 
 #### Deleting with subquery using IN / NOT IN clause
@@ -106,6 +104,14 @@ WHERE EXISTS (
     FROM DEPARTMENTS
     WHERE EMPLOYEES.DEPARTMENT = DEPARTMENTS.DEPARTMENT
 );
+
+-- Alternatively, you can delete employees using the alias 'e' for the 'EMPLOYEES' table and 'd' for the 'DEPARTMENTS' table when their department matches.
+DELETE FROM EMPLOYEES AS e
+WHERE EXISTS (
+    SELECT *
+    FROM DEPARTMENTS AS d
+    WHERE e.DEPARTMENT = d.DEPARTMENT
+);
 ```
 This deletes employees who belong to a department that exists in the departments table. In this case, it would delete employees with IDs 2 and 3.