SQL.md

SQL Cheat Sheet

Here's a quick SQL cheat sheet to help with common tasks:

Table of Contents

• 1. Basic SQL Syntax
• 2. Aggregate Functions
• 3. Grouping Data
• 4. Joins
• 5. Subqueries
• 6. Data Manipulation
• 7. Table Management

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1. Basic SQL Syntax

• Select All Columns:

  SELECT * FROM table_name;

• Select Specific Columns:

  SELECT column1, column2 FROM table_name;

• Filter Results:

  SELECT * FROM table_name WHERE condition;

• Sort Results:

  SELECT * FROM table_name ORDER BY column1 ASC|DESC;

• Limit Results:

  SELECT * FROM table_name LIMIT number;

2. Aggregate Functions

• Count Rows:

  SELECT COUNT(*) FROM table_name;

• Sum Values:

  SELECT SUM(column_name) FROM table_name;

• Average Values:

  SELECT AVG(column_name) FROM table_name;

• Minimum Value:

  SELECT MIN(column_name) FROM table_name;

• Maximum Value:

  SELECT MAX(column_name) FROM table_name;

3. Grouping Data

• Group By:

  SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name;

• Having Clause:

  SELECT column_name, COUNT(*) FROM table_name GROUP BY column_name HAVING COUNT(*) > value;

4. Joins

• Inner Join:

  SELECT columns FROM table1 INNER JOIN table2 ON table1.column = table2.column;

• Left Join:

  SELECT columns FROM table1 LEFT JOIN table2 ON table1.column = table2.column;

• Right Join:

  SELECT columns FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;

• Full Join:

  SELECT columns FROM table1 FULL JOIN table2 ON table1.column = table2.column;

5. Subqueries

• Subquery in SELECT:

  SELECT column1, (SELECT column2 FROM table2 WHERE condition) AS alias FROM table1;

• Subquery in WHERE:

  SELECT column1 FROM table1 WHERE column2 = (SELECT column2 FROM table2 WHERE condition);

6. Data Manipulation

• Insert Data:

  INSERT INTO table_name (column1, column2) VALUES (value1, value2);

• Update Data:

  UPDATE table_name SET column1 = value1 WHERE condition;

• Delete Data:

  DELETE FROM table_name WHERE condition;

7. Table Management

• Create Table:

  CREATE TABLE table_name (
      column1 datatype constraints,
      column2 datatype constraints
  );

• Drop Table:

  DROP TABLE table_name;

• Alter Table:

  ALTER TABLE table_name ADD column_name datatype;
  ALTER TABLE table_name DROP COLUMN column_name;

This should cover most of the basic and intermediate SQL tasks. Let me know if you need anything more specific!