How to Get Day Name From Weekday Number In Postgresql?

To get the day name from a weekday number in PostgreSQL, you can use the to_char function with the D argument. This argument represents the day of the week (1-7), with 1 being Sunday and 7 being Saturday.

Here is an example query that demonstrates how to get the day name from a weekday number:

SELECT to_char(to_date('3', 'D'), 'Day');

In this query, '3' represents the weekday number (Wednesday), and the to_char function converts it into the corresponding day name ('Wednesday'). You can replace '3' with any weekday number you want to get the day name for.

How to extract the day name for a weekday number using SQL functions in PostgreSQL?

You can use the to_char() function in PostgreSQL to extract the day name for a weekday number. Here's an example query to demonstrate this:

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SELECT to_char('2020-01-01'::date + i, 'Day') AS day_name
FROM generate_series(0, 6) AS gs(i);

In this query:

• We are using the generate_series() function to generate a series of numbers from 0 to 6, which represent the weekday numbers (0 for Sunday, 1 for Monday, and so on).
• We are adding these numbers to a specific date ('2020-01-01' in this example).
• We are using the to_char() function to convert the date to the day name format ('Day' as the second argument) and aliasing it as day_name.

This query will return the day names corresponding to the weekday numbers from Sunday to Saturday.

How to handle edge cases while fetching the day name from a weekday number in PostgreSQL?

When fetching the day name from a weekday number in PostgreSQL, you can handle edge cases by using a CASE statement or adding conditions to the query.

Here is an example using a CASE statement:

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SELECT 
    CASE 
        WHEN weekday_number = 1 THEN 'Sunday'
        WHEN weekday_number = 2 THEN 'Monday'
        WHEN weekday_number = 3 THEN 'Tuesday'
        WHEN weekday_number = 4 THEN 'Wednesday'
        WHEN weekday_number = 5 THEN 'Thursday'
        WHEN weekday_number = 6 THEN 'Friday'
        WHEN weekday_number = 7 THEN 'Saturday'
        ELSE 'Invalid weekday number'
    END AS day_name
FROM your_table;

In this query, we check the value of the weekday_number column and return the corresponding day name using the CASE statement. If the weekday_number is not between 1 and 7, we return 'Invalid weekday number'.

You can also add conditions to filter out invalid weekday numbers before fetching the day name:

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SELECT 
    CASE 
        WHEN weekday_number = 1 THEN 'Sunday'
        WHEN weekday_number = 2 THEN 'Monday'
        WHEN weekday_number = 3 THEN 'Tuesday'
        WHEN weekday_number = 4 THEN 'Wednesday'
        WHEN weekday_number = 5 THEN 'Thursday'
        WHEN weekday_number = 6 THEN 'Friday'
        WHEN weekday_number = 7 THEN 'Saturday'
        ELSE 'Invalid weekday number'
    END AS day_name
FROM your_table
WHERE weekday_number BETWEEN 1 AND 7;

This query will only fetch day names for weekday numbers between 1 and 7, filtering out any invalid weekday numbers.

What is the syntax to fetch the day name based on a weekday number in PostgreSQL?

In PostgreSQL, you can fetch the day name based on a weekday number using the to_char function. Here is the syntax to fetch the day name based on a weekday number:

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SELECT to_char(to_timestamp('1', 'ID'), 'Day');

In this syntax:

• to_timestamp('1', 'ID') converts the weekday number (1 for Monday, 2 for Tuesday, etc.) to a timestamp.
• 'Day' specifies the output format to return the full day name (e.g., Monday, Tuesday, etc.).

You can replace the '1' with any weekday number to fetch the corresponding day name.