How Do I Find the Data Type of a Column in SQL?

Finding the data type of a column in SQL is an essential skill for any database developer or analyst. Knowing the data type of a column allows you to understand how the data is stored and what operations can be performed on it. In this tutorial, we will explore different ways to find the data type of a column in SQL.

Using the DESCRIBE Statement

One of the simplest ways to find the data type of a column is by using the DESCRIBE statement. This statement provides information about the structure of a table, including the data types of its columns.

To use DESCRIBE, you need to know the name of the table and the specific column you want to examine. Here’s an example:

DESCRIBE employees;

This command will display a result set showing all columns in the “employees” table, along with their respective data types. You can easily identify the data type by looking at the “Type” column.

Using INFORMATION_SCHEMA.COLUMNS

Another way to find the data type of a column is by querying the INFORMATION_SCHEMA.COLUMNS view. This view contains metadata about all tables and columns in a database.

Here’s an example query using INFORMATION_SCHEMA.COLUMNS:

SELECT DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = 'employees'
AND COLUMN_NAME = 'salary';

In this query, we specify the table name and column name we want to examine. The result will be a single row containing only one value – the data type of that particular column.

Using SHOW COLUMNS FROM

If you are using MySQL, another option is to use SHOW COLUMNS FROM statement. This statement provides information about columns in a table, including their data types.

Here’s an example:

SHOW COLUMNS FROM employees;

This command will display a result set similar to DESCRIBE, showing all columns in the “employees” table and their respective data types.

Conclusion

In this tutorial, you learned several methods to find the data type of a column in SQL. The DESCRIBE statement, INFORMATION_SCHEMA.COLUMNS view, and SHOW COLUMNS FROM statement are useful tools for obtaining information about the structure of a table.

Knowing the data type of a column is crucial for performing various operations such as filtering, sorting, and joining tables. It allows you to make informed decisions about how to handle and manipulate your data effectively.

Remember to use these techniques whenever you need to determine the data type of a column in SQL.