# How to Check Column Types in PostgreSQL

> In PostgreSQL, the SELECT statement, information_schema, \d command, and pg_typeof() function are used to check the data type of a column.

PostgreSQL provides several ways to check the data type of the table’s columns. For example, the **\d** command, **information_schema** , **pg_typeof()** function, and **SELECT** query. To check/find the data type of a particular column, use the information_schema or pg_typeof() function. The “\d” command and SELECT statement retrieve the data types of all columns.

This blog post will teach you how to check the column type of a table in PostgreSQL. In this regard, the below-listed concepts will be explained with practical examples:

  * How to Check Column Type Using pg_typeof() Function?
  * How to Check Column Type Using \d Command?
  * How to Check Column Type Using SELECT Statement?
  * How to Check Column Type Using information_schema?



So, let’s begin!

 **How to Check Column Type Using pg_typeof() Function?**

pg_typeof() is a built-in function in Postgres that can accept a column as an argument and retrieves the data type of the specified column:
    
    
    SELECT pg_typeof(bike_launch_date)
    FROM public.bike_details
    LIMIT 1;

In the above snippet, “LIMIT 1” is used to avoid fluff/repetition. Omitting the LIMIT clause will retrieve the data type as many times as the column values.

The output shows that the “ **bike_launch_date** ” column has a “ **TEXT** ” data type.

 **How to Check Column Type Using \d Command?**

From SQL Shell, run the “\d” command followed by the table name to check the column types of a specific table:
    
    
    \d bike_details;

The “Type” column shows the data type of each column of the targeted table.

 **How to Check Column Type Using SELECT Statement?**

Another very convenient way to retrieve column types is to execute the SELECT query from the pgAdmin:
    
    
    SELECT * FROM bike_details;

The above query will fetch all the data of the bike_details table along with column types:

The above snippet shows the data type of each column.

 **How to Check Column Type Using information_schema?**

The information_schema can be used to check the data type of a single or all columns.

 **How to Check/Find Column Types of a Table?**

The output verifhjjies that the information schema retrieves the column names and trespective data types of the bike_details table.
    
    
    SELECT column_name, data_type
    FROM information_schema.columns
    WHERE table_schema = 'public' AND 
    table_name = 'bike_details';

The output verifies that the information schema retrieves the column names and their respective data types for the bike_details table.

 **How to Check/Find the Type of a Particular Column?**

To check the data type of only a specific column, you must specify the name of that particular column in the WHERE clause:
    
    
    SELECT column_name, data_type
    FROM information_schema.columns
    WHERE table_schema = 'public' AND 
    table_name = 'bike_details' AND
    column_name = 'bike_color';

The above query will retrieve the data type of the column named “bike_color”:

The output proves that this time, the information schema retrieves the data type of only a specific column.

 **Conclusion**

In PostgreSQL, the **SELECT** statement, **information_schema** , **\d** command, and **pg_typeof()** function are used to check the data type of a column. To check/find the data type of a particular column, use the information_schema or pg_typeof() function. The “\d” command and SELECT statement retrieve the data types of all columns. This write-up has demonstrated four different ways to check the data type of the table’s columns.

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