SQL Date and Time

SQL provides several data types for working with date and time values. The most commonly used data types for date and time are:

• DATE: stores a date in the format 'YYYY-MM-DD'.
• TIME: stores a time in the format 'HH:MI:SS'.
• DATETIME or TIMESTAMP: stores both date and time in the format 'YYYY-MM-DD HH:MI:SS'.

You can use these data types to store and retrieve date and time values in SQL queries. For example, the following SQL statement selects all records from a table where the hire_date column is after January 1st, 2021:

SELECT * FROM employees
WHERE hire_date > '2021-01-01';

You can also perform arithmetic operations on date and time values using SQL functions. For example, the following SQL statement selects all records from a table where the hire_date column is less than one year ago:

SELECT * FROM employees
WHERE hire_date < DATEADD(YEAR, -1, GETDATE());

In this example, we are using the DATEADD function to subtract one year from the current date (GETDATE()), and then comparing the result to the hire_date column.

SQL also provides several other date and time functions, such as DATEDIFF, DATEPART, and DATEADD, which allow you to manipulate date and time values in various ways. These functions can be used to calculate time differences, extract specific parts of a date or time, and perform other operations on date and time values.