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Asked: 2026-05-16T20:01:48+00:00

I have a confusing little problem in SQL-Server 2005 and Classic ASP. I have

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I have a confusing little problem in SQL-Server 2005 and Classic ASP. I have the following table in the database

+-----------+----------+----------+--------------+-------------------------+-------------------------+--------------+
| ProgramID | SystemID | ClientID | ProgramName  | ProgramStart            | ProgramEnd              | ProgramHours |
+-----------+----------+----------+--------------+-------------------------+-------------------------+--------------+
| 22        | 18       | 4        | After Gym    | 1900-01-01 09:00:00.000 | 1900-01-01 11:00:00.000 | 2hrs 0mins   |
| 23        | 18       | 4        | Free Weights | 1900-01-01 12:00:00.000 | 1900-01-01 14:00:00.000 | 2hrs 0mins   |
+-----------+----------+----------+--------------+-------------------------+-------------------------+--------------+

This basically shows a program that is assigned to a system and a client for a specific time period. What I want to do is prevent a user from entering a third program that overlaps the times already used (e.g. 10am to 11am). The creation page features drop menus for hours, minutes and am/pm for the start hour and the 3 more drop menus for the end hour. What I want to do is fire an ajax script that looks for overlapping entries when the drop menu selection changes. If it finds one it fires a js alert.

How would you detect this overlap in SQL?

Any ideas would be greatly received.

Many Thanks,
Paul

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1 Answer

  1. Editorial Team
    SELECT * FROM appointments WHERE 
(time_from <= $from and time_to >= $to) or // determine if the new appointment is fully in an exitent
(time_from <= $from and $from < time_to and time_to <= $to) or // determine if the new appointment starts in an existing and ends after
(time_from >= $from and time_to >= $to and $to > time_from) or // determine if the new appointment starts before an existing and ends in
(time_from > $from and time_to < $to) // determine if the new appointment starts before and ends after

    if more any records are selected there is an overlapping

    edit: i corrected the statement. it should now work.

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