The Ultimate SQL SELECT Cheat Sheet

Have you ever found yourself staring blankly at your SQL code, trying to recall the syntax for a SELECT query? Don’t worry; you’re not alone. SQL, with its vast array of commands and clauses, can be daunting to remember every detail. Here I will share a useful cheat sheet to write the most common SELECT queries.

The Power of a Cheat Sheet

Memorizing every SQL command and its syntax is not easy, that’s where cheat sheets come to the rescue. Instead of flipping through documentation a cheat sheet provides quick and easy access to essential commands.

Deciphering the SELECT Query

Let’s check the anatomy of a SELECT query. At its core, this query retrieves data from one or more tables in a database. Here’s a breakdown of its components:

SELECT: This keyword specifies the columns you want to retrieve from the database. You can either select specific columns or use the wildcard (*) to fetch all columns.

FROM: Here, you specify the table or tables from which you want to retrieve data.

DISTINCT (optional): This optional keyword removes duplicate rows from the result set.

WHERE(optional): This optional clause filters rows based on specified conditions. It allows you to narrow down your results to only those that meet certain criteria.

GROUP BY(optional): When you want to group your results based on the values of one or more columns, you use this clause. It’s commonly used in conjunction with aggregate functions.

HAVING(optional): Similar to the WHERE clause, HAVING filters grouped rows based on specified conditions. It comes into play after the GROUP BY clause.

ORDER BY (optional): This optional clause sorts the result set based on specified columns or expressions.

The base for a SELECT query will look like this:

Some examples

This query retrieves all columns from the employees table without applying any filtering criteria.

This query uses the DISTINCT keyword to retrieve unique values of the department_id column from the employees table.

This query filters employee records based on the salary column, only returning those with a salary greater than $50,000.

This query groups employee records by department and calculates the count of employees in each department.

This query first groups employee records by department and then filters the grouped results to only include departments with more than three employees.

This example retrieves employee records and sorts them by salary in descending order using the ORDER BY clause.

Happy querying!