Introduction to PostgreSQL boolean Data Type

The boolean data type in PostgreSQL is used to store boolean values, which represent true or false. This data type can only store one of two values. In PostgreSQL, boolean data type is one of the basic data types.

Syntax

In PostgreSQL, you can use the following syntax to create a column with boolean data type:

column_name BOOLEAN

Use Cases

The boolean data type is commonly used to store data with two possible states. For example, switch status (on or off), completion status (completed or not), etc. In queries, boolean data type can be used as conditions in WHERE clauses. It can also be used in comparison with other data types such as strings or numbers.

Examples

Here are two examples of using boolean data type:

1. Storing switch status

   Let’s assume we have a table called switch with two columns, id and is_on. You can create this table using the following command:

   CREATE TABLE switch (
     id SERIAL PRIMARY KEY,
     is_on BOOLEAN
   );
   

   Next, you can insert values into the is_on column:

   INSERT INTO switch (is_on) VALUES (true);
   INSERT INTO switch (is_on) VALUES (false);
   

   You can retrieve the values of the is_on column using the following query:

   SELECT id, is_on FROM switch;
   

   This query will return the following result:

    id | is_on
   ----+-------
     1 | true
     2 | false

2. Storing completion status

   Let’s assume we have a table called tasks with two columns, id and completed. You can create this table using the following command:

   CREATE TABLE tasks (
     id SERIAL PRIMARY KEY,
     completed BOOLEAN
   );
   

   Next, you can insert values into the completed column:

   INSERT INTO tasks (completed) VALUES (false);
   INSERT INTO tasks (completed) VALUES (true);
   

   You can retrieve the values of the completed column using the following query:

   SELECT id, completed FROM tasks;
   

   This query will return the following result:

    id | completed
   ----+----------
     1 | false
     2 | true
   

Conclusion

The boolean data type is a basic data type in PostgreSQL used to store boolean values. It is commonly used to store data with two possible states and can be used in conjunction with other data types.