Detailed SQL Cheat Sheet

Here’s a detailedSQL Cheat Sheet you can use for your blog post:

SQL Cheat Sheet

***1. Basic SQL Commands***

- ***SELECT*** : Retrieves data from a database.

  SELECT column1, column2 FROM table;

- ***WHERE*** : Filters records.

  SELECT * FROM table WHERE condition;

- ***INSERT INTO*** : Adds new records.

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

- ***UPDATE*** : Modifies existing records.

  UPDATE table SET column1 = value WHERE condition;

- ***DELETE*** : Removes records.

  DELETE FROM table WHERE condition;

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***2. SQL Clauses***

- ***ORDER BY*** : Sorts results.

  SELECT * FROM table ORDER BY column ASC|DESC;

- ***GROUP BY*** : Groups rows that share values.

  SELECT column, COUNT(*) FROM table GROUP BY column;

- ***HAVING*** : Filters groups (used with GROUP BY).

  SELECT column, COUNT(*) FROM table GROUP BY column HAVING COUNT(*) > 1;

- ***LIMIT*** : Limits the number of results.

  SELECT * FROM table LIMIT 10;

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***3. Joins***

- ***INNER JOIN*** : Returns matching records from both tables.

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

- ***LEFT JOIN*** : Returns all records from the left table and matching records from the right.

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

- ***RIGHT JOIN*** : Returns all records from the right table and matching records from the left.

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

- ***FULL JOIN*** : Returns all records when there's a match in either table.

  SELECT * FROM table1
  FULL OUTER JOIN table2 ON table1.column = table2.column;

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***4. Aggregate Functions***

- ***COUNT()*** : Returns the number of rows.

  SELECT COUNT(*) FROM table;

- ***SUM()*** : Returns the total sum of a numeric column.

  SELECT SUM(column) FROM table;

- ***AVG()*** : Returns the average value.

  SELECT AVG(column) FROM table;

- ***MAX() / MIN()*** : Returns the highest/lowest value.

  SELECT MAX(column), MIN(column) FROM table;

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***5. Subqueries***

- ***Subquery in WHERE clause*** :

  SELECT * FROM table1 WHERE column IN (SELECT column FROM table2);

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***6. Table Management***

- ***CREATE TABLE*** : Creates a new table.

  CREATE TABLE table_name (
    column1 datatype,
    column2 datatype
  );

- ***ALTER TABLE*** : Modifies an existing table.

  ALTER TABLE table_name ADD column datatype;

- ***DROP TABLE*** : Deletes a table.

  DROP TABLE table_name;

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***7. Indexes***

- ***CREATE INDEX*** : Adds an index to a table.

  CREATE INDEX index_name ON table_name (column);

- ***DROP INDEX*** : Removes an index.

  DROP INDEX index_name;

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***8. Data Types (Commonly Used)***

- ***INT*** : Integer numbers.
• VARCHAR(size) : Variable-length string.
• DATE : Date in ‘YYYY-MM-DD’ format.
• DECIMAL(size, d) : Decimal numbers, specifying precision.

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This cheat sheet covers essential SQL commands and functions for working with databases. Whether you’re querying data, joining tables, or managing databases, these commands will help streamline your tasks!