How to write loop statements in SQL

There are no traditional loop statements in SQL, but you can simulate loops using recursive CTE: create a recursive CTE that contains a "iteration" column to track the number of loops. Recursive query updates the "iteration" column and satisfies the loop condition. Use the SELECT statement to select the required data from the CTE.

Loop statements in SQL

There are no traditional loop statements in SQL, such as while() or for(). However, loop statements can be simulated by using recursive common table expressions (CTEs).

Write loop statements using CTE

To write a loop statement using CTE, the following steps are required:

1. Create a recursive CTE: Create a CTE with a column named "iteration" to track the number of loops.
2. Recursive query: Write a recursive query in the CTE that updates the "iteration" column and meets the required loop conditions.
3. Reference CTE: Use a SELECT statement to select the required data from the CTE.

Example:

Suppose we want to create a loop that prints the numbers 1 to 10:

 <code class="sql">WITH RECURSIVE numbers AS ( SELECT 1 AS iteration UNION ALL SELECT iteration 1 FROM numbers WHERE iteration </code>

Perform steps:

1. Create a CTE named "numbers" with the initial "iteration" value of 1.
2. Use a recursive query to update the "iteration" column and check the loop conditions (iteration
3. Use the SELECT statement to select the "iteration" column from the CTE.

The result will be a table with numbers from 1 to 10.

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