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SQL Data Types

SQL Data Types

SQL data types are an attribute that specifies the type of data that a particular column can hold in a SQL database. It is crucial to understand various data types in SQL and how to use them appropriately. This article will walk through the most common SQL data types and provide examples of their use.

Numeric Data Types​

Numeric data types are used to store numeric values. It is very important to make sure the range of your data is between the minimum and maximum values of numeric data types. Here are some examples of numeric data types:

  • INT: An integer data type that can hold whole numbers, both positive and negative. For example, age INT.

  • DECIMAL or NUMERIC: These data types are used to hold numeric values with decimal points. For example, price DECIMAL(5,2).

  • FLOAT: A floating point number that can hold real numbers. For example, weight FLOAT.

  • REAL or DOUBLE PRECISION: These data types are used to hold real numbers with larger precision.

Date and Time Data Types​

Date and Time data types are used to store date and/or time. Here are some examples:

  • DATE: It is used to store date values. For example, birth_date DATE.

  • TIME: It is used to store time values. For example, appointment_time TIME.

  • DATETIME: It is used to store date and time values. For example, appointment DATETIME.

String Data Types​

String data types are used to store alphanumeric characters. Here are some examples:

  • CHAR: It is used to store fixed length of characters. For example, gender CHAR(1).

  • VARCHAR: It is used to store variable length of characters. For example, first_name VARCHAR(30).

  • TEXT: It is used to store long text entries.

Unicode Character String Types​

Unicode character string types are used to store Unicode characters. Here are some examples:

  • NCHAR: It is used to store fixed number of Unicode characters.

  • NVARCHAR: It is used to store variable number of Unicode characters.

  • NTEXT: It is used to store long Unicode text.

Binary Data Types​

Binary data types are used to store binary data. Here are some examples:

  • BINARY: It is used to store fixed size binary data.

  • VARBINARY: It is used to store variable size binary data.

  • IMAGE: It is used to store binary data as images.

Other Data Types​

  • BOOLEAN: It is used to store Boolean values true or false.

  • BIT: An integer that can hold 0, 1, or NULL.

Conclusion​

Understanding SQL data types is an essential part of dealing with SQL databases. It helps to ensure that the data you are inserting into your database is of the correct type, which can prevent errors and aid in maintaining data integrity.

The next step after understanding data types is to learn how to create and manipulate tables using these data types. This involves understanding SQL commands such as CREATE, ALTER, and DROP, among others. Practice using these data types and commands to become more comfortable with SQL databases.