This section provides a comprehensive guide to SQL (Structured Query Language) references, including syntax, functions, and best practices.

Common SQL Commands

  • SELECT: Retrieve data from a database.
  • INSERT: Add new data into a database.
  • UPDATE: Modify existing data in a database.
  • DELETE: Remove data from a database.

Functions

  • COUNT(): Returns the number of rows.
  • SUM(): Returns the sum of a numeric column.
  • AVG(): Returns the average value of a numeric column.
  • MAX(): Returns the maximum value in a column.
  • MIN(): Returns the minimum value in a column.

Data Types

  • INT: Integer.
  • VARCHAR: Variable-length string.
  • DATE: Date and time.
  • BOOLEAN: True or false.

For more detailed information, please visit our SQL Tutorial.

Example

Here is a simple SQL query to retrieve all columns from a table named "users":

SELECT * FROM users;

SQL Syntax