MySQL TIMESTAMP() Function

The TIMESTAMP() function in MySQL is used to return a datetime value based on a specified date (and optionally a time) value.

Purpose: The function combines a date (or datetime) value with an optional time value to return a complete datetime value. If only a date is provided, it returns that date with the default time of 00:00:00.
Syntax: TIMESTAMP(expression, time)

TIMESTAMP(expression, time)

expression: A required date or datetime value.
time: An optional time value to add to the expression. If provided, the time value will be combined with the date value to create a complete datetime.

Works in: From MySQL 4.0 onwards.
Return Type: Returns a DATETIME value, combining both the date and time components.
Behavior:
- If only the date (expression) is provided, the function returns that date with the default time 00:00:00.
- If both the date and time are provided, it returns a DATETIME value by combining the two.

SELECT TIMESTAMP("2017-07-23", "13:10:11");

Result:

2017-07-23 13:10:11

Explanation: The date 2017-07-23 is combined with the time 13:10:11 to return a complete datetime value.

SELECT TIMESTAMP("2017-07-23");

Result:

2017-07-23 00:00:00

Explanation: Since no time is provided, the function returns the date 2017-07-23 with the default time 00:00:00.

Creating Complete Datetime: When you have a date value and want to combine it with a specific time (e.g., event start date with time).
Data Formatting: Useful for formatting and combining date and time values for consistent output in reports and databases.
Default Time Handling: When you want to assign a default time (00:00:00) to a date in cases where only the date is provided.

The TIMESTAMP() function is different from the CURRENT_TIMESTAMP function, which returns the current date and time of the server.
This function will not adjust time zones; the result will be based on the system's current time zone unless explicitly handled.