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Ok, I have it down, on how to perform my update for dates, based on column values:<br />
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&nbsp; &nbsp; &nbsp; &nbsp; UPDATE TL_Calibration SET [Next Calib] = DATEADD(day, InspectionFrequency, [Last Calibrated])<br />
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The question I have now is how to take two columns, with date values, and insert the difference into a column. &nbsp;Here is an example of what I am talking about:<br />
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[Last Calibrated] &nbsp; &nbsp; &nbsp; &nbsp;[Next Calib] &nbsp; &nbsp;= &nbsp; &nbsp; Days<br />
--------------------------<wbr />----------<wbr />----------<wbr />----------<wbr />---<br />
&nbsp; &nbsp; 04/01/05 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;04/05/05 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;4 &nbsp; &nbsp; &nbsp; &lt;------WHERE &quot;4&quot; IS HOW MANY DAYS LEFT &nbsp; &nbsp; &nbsp;<br />

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Ok, I have it down, on how to perform my update for dates, based on column values:

        UPDATE TL_Calibration SET [Next Calib] = DATEADD(day, InspectionFrequency, [Last Calibrated])

The question I have now is how to take two columns, with date values, and insert the difference into a column.  Here is an example of what I am talking about:

[Last Calibrated]        [Next Calib]    =     Days
-----------------------------------------------------------
    04/01/05                04/05/05                4       <------WHERE "4" IS HOW MANY DAYS LEFT      


add/sub value of 2 columns and get difference

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