SQL cheat sheet

Querying Data in SQL

SELECT

Retrieve data from one or more tables

1
SELECT * FROM employees;

DISTINCT

Select unique values from a column

1
2
SELECT DISTINCT department FROM
employees;

WHERE

Filter rows based on specified conditions

1
2
SELECT * FROM employees WHERE
salary > 55000.00;

LIMIT

Limit the number of rows returned in the result set

1
SELECT * FROM employees LIMIT 3;

FETCH

Retrieve a specified number of rows from the result set

1
SELECT * FROM employees FETCH FIRST 3 ROWS ONLY;

Filtering Data in SQL

WHERE

Filter rows based on specified conditions

1
SELECT * FROM employees WHERE department = 'IT';

LIKE

Match a pattern in a column

1
SELECT * FROM employees WHERE first_name LIKE 'J%';

IN

Match any value in a list

1
SELECT * FROM employees WHERE department IN ('HR', 'Finance');

BETWEEN

Match values within a specified range

1
SELECT * FROM employees WHERE salary BETWEEN 50000 AND 60000;

IS NULL

Match NULL values

1
SELECT * FROM employees WHERE department IS NULL;

SQL Operator

AND

Combines multiple conditions in a WHERE clause

1
2
3
SELECT * FROM employees WHERE
department = 'IT' AND salary >
60000;

OR

Specifies multiple conditions where any one of them should be true

1
2
3
SELECT * FROM employees WHERE
department = 'HR' OR department =
'Finance';

NOT

Negates A Condition SELECT * FROM employees WHERE NOT department = ‘IT’; ORDER BY Sorts the Result Set in Ascending or Descending Order SELECT * FROM employees ORDER BY salary DESC; GROUP BY Groups Rows that have the Same Values into Summary Rows SELECT department, COUNT(*) AS employee_count FROM employees GROUP BY department;

Aggregation Data in SQL

COUNT

Count the number of rows in a result set

1
SELECT COUNT(*) FROM employees;

SUM

Calculate the sum of values in a column

1
SELECT SUM(salary) FROM employees;

AVG

Calculate the average value of a column

1
SELECT AVG(salary) FROM employees;

MIN

Find the minimum value in a column

1
SELECT MIN(salary) FROM employees;

MAX

Find the maximum value in a column

1
SELECT MAX(salary) FROM employees;