A Look Into SQL’s Order Of Execution
towardsdatascience.com/a-look-into-sqls-order-of-execution-d0b81e361c66
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The order in which the clauses in queries are executed is as follows: 1. FROM/JOIN: The FROM and/or JOIN clauses are executed first to determine the data of interest. 2. WHERE: The WHERE clause is executed to filter out records that do not meet the constraints. 3. GROUP BY: The GROUP BY clause is executed to group the data based on the values in one or more columns. 4. HAVING: The HAVING clause is executed to remove the created grouped records that don’t meet the constraints. 5. SELECT: The SELECT clause is executed to derive all desired columns and expressions. 6. ORDER BY: The ORDER BY clause is executed to sort the derived values in ascending or descending order. 7. LIMIT/OFFSET: Finally, the LIMIT and/or OFFSET clauses are executed to keep or skip a specified number of rows.
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