How to Select Dates Between Two Dates in PostgreSQL?

When managing a PostgreSQL database, we may often encounter scenarios where we need to filter data based on date ranges. This could be for generating reports, analyzing trends, or retrieving time–sensitive information. However, querying for data within a specific date range can be a challenging task, especially when dealing with large datasets.

In this article, we will explore three different approaches to selecting dates between two dates in PostgreSQL. Each approach offers its own advantages and use cases, allowing you to choose the method that best suits our specific requirements.

How to Find the Interval Between Two Dates in PostgreSQL?

When working with PostgreSQL databases, it’s often necessary to query for data within a specific date range. One of the key challenges is ensuring that the query is both accurate and efficient. If not optimized correctly, the query could result in slow performance and increased resource consumption.

Below is the method which helps us to Find the Interval Between Two Dates in PostgreSQL are as follows:

1. Using the BETWEEN Clause
2. Using Comparison Operators
3. Casting Date Values

Now let’s create a sample table in PostgreSQL and perform multiple dates operations on them:

Create table.

CREATE TABLE events (
    event_id SERIAL PRIMARY KEY,
    event_name VARCHAR(100),
    event_date DATE
);

Insert data into table.

INSERT INTO events (event_name, event_date) VALUES
    ('Event 1', '2023-01-15'),
    ('Event 2', '2023-02-20'),
    ('Event 3', '2023-03-25'),
    ('Event 4', '2023-04-10'),
    ('Event 5', '2023-05-05');

The table is created successfully:

Events Table

1. Using the BETWEEN Clause

The Between clause PostgreSQL permits us to select the values that are between a specified range. This part of the clause is very helpful when we are retrieving records of specific dates. we can use this clause to gather the documents that are between two dates.

Syntax:

SELECT * FROM table_name WHERE date_column BETWEEN 'start_date' AND 'end_date';

• table_name : Write your table’s name.
• date_column : Write the name of the column that contains dates.
• Specify start_date and the end_date respectively.

Example: Query to list down the events that fall within the dates of February 1, 2023, to April 30, 2023.

SELECT * FROM events WHERE event_date BETWEEN '2023-02-01' AND '2023-04-30';

Output:

Using the BETWEEN Clause

Explanation: This statement will generate all events that have occurred in the dates range from February 1, 2023 to April 30, 2023.

2. Using Comparison Operators

The other alternative is to use comparison operators like >= (greater than or equal to) and <= (less than or equal to) in order to declare the same thing.

Syntax:

SELECT * FROM table_name WHERE date_column >= 'start_date' AND date_column <= 'end_date';

This method explicitly specifies the boundaries of the date range.

Example: Query achieves the same result as the previous one, using comparison operators instead of BETWEEN

SELECT * FROM events WHERE event_date >= '2023-02-01' AND event_date <= '2023-04-30';

Output:

Using Comparison Operators

Explanation: Hence, this query following column “events” shows all the events which happens between Feb 1, 2023 and April 30, 2023.

3. Casting Date Values

As long as the column values are correctly casted to the DATE type, we can be sure that they are properly formatted already. PostgreSQL provides the ::DATE syntax for this purpose.

Syntax:

SELECT * FROM table_name WHERE date_column::DATE BETWEEN 'start_date'::DATE AND 'end_date'::DATE;

• table_name: Write your table’s name.
• date_column: Write the name of the column that contains dates.
• Specify start_date and the end_date respectively.

Example: Query retrieves the events between February 1, 2023, and April 30, 2023, casting date values explicitly.

SELECT * FROM events WHERE event_date::DATE BETWEEN '2023-02-01'::DATE AND '2023-04-30'::DATE;

Output:

Casting Date Values

Explanation: Such a query will list the events, which refers to all columns of the events table, where the event_date occurs in the dates between February 1, 2023 and April 30, 2023.

4. Inclusive and Exclusive Range

Be aware, what kind of scope do we want to have, inclusive or exclusive of both start and end dates. The BETWEEN clause is inclusive, so it covers records starting from one day and going up to the second one. In an exclusive range, either the start or the end point (or both) is not included. Set necessary conditions if exclusivity is required by using < (greater than) and > (less) operators.

Conclusion

Selecting dates between two dates in PostgreSQL involves utilizing SQL clauses such as BETWEEN or comparison operators. Ensure proper data type casting and consider indexing for optimized performance, especially with large datasets. By understanding these techniques, you can efficiently query date ranges and retrieve the desired records from your PostgreSQL database.