What does as mean in mysql

ASAS in MySQL is a keyword used to create an alias or specify a new table name. It improves readability, avoids ambiguity, performs temporary renaming, and creates table aliases. Aliases created using AS are only valid within the current query by default, but permanent aliases can be created using the CREATE ALIAS statement.

AS in MySQL

AS is a keyword in MySQL, used Used to specify a new name for an alias or table. It allows you to create temporary or persistent names to make it easier to reference objects in queries.

Usage

Syntax:

<code class="sql">SELECT ... AS alias_name
FROM ...</code>

Example:

Will The name column of table customers is renamed to customer_name:

<code class="sql">SELECT name AS customer_name
FROM customers;</code>

Function

Use AS Has the following advantages:

• Improve readability: By creating meaningful aliases, you can improve the readability of your query, making it easier to understand.
• Avoid ambiguity: AS can be used to unambiguously refer to a specific object when tables or columns have the same name.
• Temporary renaming: AS provides a way to temporarily rename objects without permanently modifying the database schema.
• Table alias: AS can be used to create table aliases to simplify JOIN operations.

Persistence

By default, aliases created using AS are only valid within the current query. However, you can use the CREATE ALIAS statement to create a persistent alias that will persist in the database.

Syntax:

<code class="sql">CREATE ALIAS alias_name AS new_name;</code>

Example:

Create a permanent alias cust to reference customers table:

<code class="sql">CREATE ALIAS cust AS customers;</code>

Now you can use cust as an alias for the customers table:

<code class="sql">SELECT *
FROM cust;</code>

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