SQL Data Types (2024)

FAQs

What is the best practice of data types in SQL? ›

A best practice is to “right size” data types by asking business questions and determining the data types that are best suited to the organization's and application's needs. Right-sizing can result in tremendous storage savings, which can lead to faster database performance.

The data type is a guideline for SQL to understand what type of data is expected inside of each column, and it also identifies how SQL will interact with the stored data. In MySQL there are three main data types: string, numeric, and date and time.

Note: SQL Server will deprecate ntext, text and image data type in future releases. We should avoid the use of these data types. You can use Nvarchar(max), varchar(max), and varbinary(max).

The general rule of thumb for choosing a data type for the columns in your tables is to choose the data type that most closely matches the domain of correct values for the column. That means you should try to adhere to the following rules: If the data is numeric, favor SMALLINT, INTEGER, BIGINT, or DECIMAL data types.

A data type is an attribute that specifies the type of data that the object can hold: integer data, character data, monetary data, date and time data, binary strings, and so on. SQL Server supplies a set of system data types that define all the types of data that can be used with SQL Server.

The data type is a guideline for SQL to understand what type of data is expected inside of each column, and it also identifies how SQL will interact with the stored data. Note: Data types might have different names in different database. And even if the name is the same, the size and other details may be different!

Real data can hold a value 4 bytes in size, meaning it has 7 digits of precision (the number of digits to the right of the decimal point). It's also a floating-point numeric that is identical to the floating point statement float(24).

What is VARCHAR in SQL? ›

Varchar is a datatype in SQL that holds characters of variable length. This data type stores character strings of up to 255 bytes in a variable-length field. The data can consist of letters, numbers, and symbols. It uses dynamic memory location.

SQL numeric data types are used to store numeric values in a database. The most commonly used numeric data types are INT and FLOAT . The INT data type is used to store whole numbers, while the FLOAT data type is used to store decimal numbers. The INT data type can store values ranging from -2^31 to 2^31-1.

"The NUMBER data type stores zero as well as positive and negative fixed numbers with absolute values from 1.0 x 10^-130 to but not including 1.0 x 10^126." "The precision p can range from 1 to 38. The scale s can range from -84 to 127."

1. Use Meaningful Alias Names. A key principle of writing clean SQL queries is using meaningful aliases for tables and columns. This practice improves query readability and helps others understand your code more easily.

According to the 2023 Developer Survey by Stack Overflow, PostgreSQL is the best database, followed by MySQL and SQLite.