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 task is crucial 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.

Here, we will explore three different approaches on how to select 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:

Now let's create a sample table in PostgreSQL named 'events' and perform multiple date operations on them.

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

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.
• start_date and end_date: The range boundaries.

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:

Explanation: This statement will generate all events that have occurred between February 1, 2023, and 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. This method explicitly specifies the boundaries of the date range.

Syntax:

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

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:

Explanation: This query will list all events that occurred between February 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.
• start_date and end_date: The range boundaries.

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:

Explanation: This query will list events where the event_date occurs between February 1, 2023, and April 30, 2023.

Inclusive and Exclusive Range

Be aware of the scope you need: inclusive or exclusive of both start and end dates. The BETWEEN clause is inclusive, meaning it includes both boundaries. For an exclusive range, you can use '<' (less than) and '>' (greater than) operators.

Exclusive Range Example:

SELECT * FROM events WHERE event_date > '2023-01-31' AND event_date < '2023-05-01';

Conclusion

In 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.