PostgreSQL TIMEOFDAY Date/Time Function

PostgreSQL TIMEOFDAY Date/Time Function

The PostgreSQL TIMEOFDAY function is used to retrieve the current date and time as a text string. This function is similar to CLOCK_TIMESTAMP but returns the result as a text string, which can be useful for logging or display purposes.

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Syntax

TIMEOFDAY()

The TIMEOFDAY function does not take any arguments and returns the current date and time as a text string.

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Example PostgreSQL TIMEOFDAY Queries

Let's look at some examples of PostgreSQL TIMEOFDAY function queries:

1. Basic TIMEOFDAY Example

SELECT TIMEOFDAY() AS current_time_text;

This query retrieves the current date and time as a text string.

2. TIMEOFDAY with Column Values

SELECT id, name, TIMEOFDAY() AS query_time_text
FROM people;

This query retrieves the id, name, and the current date and time as a text string for each row in the people table.

3. TIMEOFDAY in Conditional Statements

SELECT id, name
FROM events
WHERE event_time::text < TIMEOFDAY();

This query retrieves the id and name of events that are scheduled to occur before the current date and time as a text string.

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Full Example

Let's go through a complete example that includes creating a table, inserting data, and using the TIMEOFDAY function to capture the current date and time as a text string.

Step 1: Creating a Table

This step involves creating a new table named people to store people's data.

CREATE TABLE people (
    id SERIAL PRIMARY KEY,
    name TEXT
);

In this example, we create a table named people with columns for id and name.

Step 2: Inserting Data into the Table

This step involves inserting some sample data into the people table.

INSERT INTO people (name)
VALUES ('Alice'),
       ('Bob'),
       ('Charlie');

Here, we insert data into the people table.

Step 3: Using the TIMEOFDAY Function

This step involves using the TIMEOFDAY() function to capture the current date and time during the execution of queries.

Retrieve current time as text:

SELECT TIMEOFDAY() AS current_time_text;

This query retrieves the current date and time as a text string.

Capture current time as text with column values:

SELECT id, name, TIMEOFDAY() AS query_time_text
FROM people;

This query captures the current date and time as a text string for each row in the people table.

Retrieve events occurring before the current time as text:

SELECT id, name
FROM events
WHERE event_time::text < TIMEOFDAY();

This query retrieves the id and name of events that are scheduled to occur before the current date and time as a text string.

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Conclusion

The PostgreSQL TIMEOFDAY() function is a fundamental tool for retrieving the current date and time as a text string. Understanding how to use the TIMEOFDAY() function and its syntax is essential for accurate time-based operations and logging in PostgreSQL databases.