SQL Waitfor

Introduction

SQL Waitfor is a command that is used to delay the execution of a SQL statement or a batch of statements for a specified amount of time or until a specific time. This can be useful when coordinating processes or waiting for resources to become available.

Syntax

WAITFOR DELAY 'time'
WAITFOR TIME 'time'

Parameters

• DELAY - Specifies the amount of time to wait before executing the next SQL statement or batch of statements. The time is specified in the format HH:MI:SS.mmm, where HH represents hours, MI represents minutes, SS represents seconds, and mmm represents milliseconds. For example, WAITFOR DELAY '00:00:05.000' will delay for 5 seconds.

• TIME - Specifies the exact time to wait for before executing the next SQL statement or batch of statements. The time is specified in the format HH:MI:SS.mmm, where HH represents hours, MI represents minutes, SS represents seconds, and mmm represents milliseconds. For example, WAITFOR TIME '23:59:59.999' will wait until the end of the day before executing the next statement.

Examples

Example 1: Delay Execution

SELECT 'Start'
WAITFOR DELAY '00:00:05.000'
SELECT 'End'

This code will display the message 'Start', wait for 5 seconds, and then display the message 'End'.

Example 2: Wait for Specific Time

SELECT 'Start'
WAITFOR TIME '23:59:59.999'
SELECT 'End'

This code will display the message 'Start' and then wait until the end of the day before displaying the message 'End'.

Conclusion

SQL Waitfor is a useful command for coordinating processes and waiting for resources to become available. By delaying the execution of SQL statements or waiting for a specific time, you can ensure that your SQL code runs smoothly and efficiently.