SQL - Order Of Execution Of A Query

Order Of Execution Of A Query

SELECT DISTINCT column, AGG_FUNC(column_or_expression), …

FROM mytable

    JOIN another_table

      ON mytable.column = another_table.column

    WHERE constraint_expression

    GROUP BY column

    HAVING constraint_expression

    ORDER BY column ASC/DESC

    LIMIT count OFFSET COUNT;

Because each part of the query is executed sequentially, it's important to understand the order of execution so that you know what results are accessible where.

Query order of execution

1. FROM and JOINs

2. WHERE

3. GROUP BY

4. HAVING

5. SELECT

6. DISTINCT

7. ORDER BY

8. LIMIT / OFFSET

Conclusion

Not every query needs to have all the parts, it allows developers and data analysts to quickly manipulate data without having to write additional code, just by using the above clauses.