SQL Basics
SQL Data Types
SQL Data Types Overview
SQL data types include INT, VARCHAR, and DATE, covering numeric and string data for structuring tables.
Introduction to SQL Data Types
In SQL, data types define the kind of data that can be stored in a table's columns. They help ensure accuracy and consistency of data, enabling efficient data management. Common data types include INT for integers, VARCHAR for variable-length strings, and DATE for date values.
Numeric Data Types
Numeric data types are used to store numeric values. The most frequently used numeric types are:
- INT: Used for integer values. Example: 123
- FLOAT: Used for floating-point numbers. Example: 123.45
- DECIMAL: Used for fixed-point numbers. Example: 123.45 (with a specified scale and precision)
String Data Types
String data types store sequences of characters. Common types include:
- CHAR(n): Fixed-length string of length n. Pads with spaces if the input is shorter.
- VARCHAR(n): Variable-length string with a maximum length of n.
- TEXT: Used for large strings.
Date and Time Data Types
Date and time data types are essential for handling temporal data. Key types include:
- DATE: Stores date values (year, month, day).
- TIME: Stores time values (hours, minutes, seconds).
- DATETIME: Stores both date and time.
Choosing the Right Data Type
Choosing the appropriate data type is crucial for database design. Consider the nature of the data and the required operations. For example, use INT for IDs, VARCHAR for names, and DATE for birthdays to optimize storage and performance.
