SQL Basic Cheat Sheet

Posted by admin on 2023-07-17 19:00:39 |

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Certainly! Here is a basic cheat sheet for SQL queries:

SELECT Statement:

• Retrieve data from a table:

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  SELECT column1, column2 FROM table_name;
  

• Retrieve all columns from a table:

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  SELECT * FROM table_name;
  

WHERE Clause:

• Filter rows based on a condition:

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  SELECT column1, column2 FROM table_name WHERE condition;
  

• Comparison operators: =, <> (not equal to), <, >, <=, >=

Logical Operators:

• Combine multiple conditions:
  • AND operator:

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    WHERE condition1 AND condition2;
    

  • OR operator:

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    WHERE condition1 OR condition2;
    

  • NOT operator:

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    WHERE NOT condition;
    

ORDER BY Clause:

• Sort the result set:

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  SELECT column1, column2 FROM table_name ORDER BY column1 ASC/DESC;
  

  ASC: Ascending order (default), DESC: Descending order

LIMIT Clause:

• Limit the number of rows returned:

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  SELECT column1, column2 FROM table_name LIMIT number_of_rows;
  

GROUP BY Clause:

• Group rows based on a column:

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  SELECT column1, aggregate_function(column2) FROM table_name GROUP BY column1;
  

  Common aggregate functions: COUNT, SUM, AVG, MIN, MAX

JOIN Clause:

• Combine rows from multiple tables based on a related column:
  • Inner Join:

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    SELECT column1, column2 FROM table1 JOIN table2 ON table1.column = table2.column;
    

  • Left Join:

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    SELECT column1, column2 FROM table1 LEFT JOIN table2 ON table1.column = table2.column;
    

  • Right Join:

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    SELECT column1, column2 FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;
    

  • Full Outer Join:

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    SELECT column1, column2 FROM table1 FULL OUTER JOIN table2 ON table1.column = table2.column;
    

UPDATE Statement:

• Update values in a table:

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  UPDATE table_name SET column1 = value1, column2 = value2 WHERE condition;
  

DELETE Statement:

• Delete rows from a table:

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  DELETE FROM table_name WHERE condition;
  

These are just some of the most commonly used SQL query commands and clauses. SQL is a powerful language with many more features and syntax options.