SQL Queries Cheat Sheet

Standard SQL commands for database management and querying

Basic Queries

SELECT * FROM table_name;Select all columns from a table

SELECT col1, col2 FROM table_name;Select specific columns

SELECT DISTINCT column FROM table;Select distinct values

SELECT * FROM table WHERE condition;Filter results

INSERT INTO table (col1, col2) VALUES (val1, val2);Insert new row

UPDATE table SET col1 = val1 WHERE condition;Update existing rows

DELETE FROM table WHERE condition;Delete rows

TRUNCATE TABLE table_name;Empty a table

SELECT * FROM t1 INNER JOIN t2 ON t1.id = t2.id;Inner Join (matches only)

SELECT * FROM t1 LEFT JOIN t2 ON t1.id = t2.id;Left Join (all from left)

SELECT * FROM t1 RIGHT JOIN t2 ON t1.id = t2.id;Right Join (all from right)

SELECT * FROM t1 FULL OUTER JOIN t2 ON t1.id = t2.id;Full Join (all from both)

SELECT COUNT(*) FROM table;Count rows

SELECT SUM(col) FROM table;Sum values

SELECT AVG(col) FROM table;Average value

SELECT col, COUNT(*) FROM table GROUP BY col;Group rows

SELECT col, COUNT(*) FROM table GROUP BY col HAVING COUNT(*) > 5;Filter groups

CREATE TABLE table (id INT, name VARCHAR(50));Create table

ALTER TABLE table ADD column_name datatype;Add column

DROP TABLE table_name;Delete table

CREATE INDEX idx_name ON table (column);Create index