Proper Comparisons for Dates in Merge Fields

Volker is having a problem comparing dates in a merge field. His database contains a Birthdate field, which (obviously) contains a birth date for each person in the database. As he merges each record, he wants to compare the Birthdate field to a reference date, and then take some action based on the result. The logic he is attempting to use looks like this:

{IF {MERGEFIELD Birthdate} > "02/26/1996" "Under 30" "Over 30"}

The problem is that the comparison doesn't work properly; it doesn't return consistent results. In most cases, Word is doing a text comparison, not a true date comparison. That means you need to make sure that both values being compared are in the same, consistent format.

One possible solution is to use a format switch in the merge field, in the following manner:

{IF {MERGEFIELD Birthdate \@ "MM/dd/yyyy"} > "02/26/1996" "Under 30" "Over 30"}

This puts the incoming information into a comparable format. The results you get from this approach may depend, however, on characteristics of the data source, independent of Word.

In many cases, you'll get the best results by putting the dates into a year-first, no-separator format (so that a text comparison behaves the same as a date comparison). For instance:

{IF {MERGEFIELD Birthdate \@ "yyyyMMdd"} > "19960226" "Under 30" "Over 30"}

If you need a more explicit comparison, you can use the COMPARE field to compare the two values (again, after you format them consistently). This example compares the Birthdate to the same reference date:

{IF {COMPARE {MERGEFIELD Birthdate \@ "yyyyMMdd"} "19960226"} = 1 "Under 30" "Over 30"}

You can even compare to the current date by using the DATE field, like this:

{IF {COMPARE {MERGEFIELD Birthdate \@ "yyyyMMdd"} {DATE \@ "yyyyMMdd"}} = 1 "Date Is Later" "Date Is Earlier"}

If the comparison still yields inconsistent results, then the only solution may be to do a mathematical conversion on the date (actually, on both Birthdate and the reference date) so that you have an actual numeric comparison. You can do this by converting the date into a Julian value, which requires a very complex merge field, like the one shown here:

{IF {QUOTE {SET a{=INT((14-{MERGEFIELD BIRTHDATE \@ M})/12)}}
{SET b{={MERGEFIELD BIRTHDATE \@ yyyy}+4800-a}}
{SET c{={MERGEFIELD BIRTHDATE \@ M}+12*a-3}}
{SET d{MERGEFIELD BIRTHDATE \@ d}}
{SET jd{=d+INT((153*c+2)/5)+365*b+INT(b/4)-INT(b/100)+INT(b/400)-32045}}
{jd \#,0}} > 2,443,056 "over 30" "under30"}

Such an approach may look intimidating, but is just the brute-force method necessary for some instances.

WordTips is your source for cost-effective Microsoft Word training. (Microsoft Word is the most popular word processing software in the world.) This tip (9995) applies to Microsoft Word 2007, 2010, 2013, 2016, 2019, 2021, 2024, and Word in Microsoft 365. You can find a version of this tip for the older menu interface of Word here: Proper Comparisons for Dates in Merge Fields.