I’ve come from a background of microsoft access, SQL Server and ASP programming so am pretty familiar with the concept of NULL.
I’ve recently been working on some Excel VBA code and was puzzled when an empty cell would be reported as not being NULL or empty string.
For anyone else coming across this problem have a look at the vbNullString constant which seems to replace NULL in some cases.
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In the case I was having trouble with IsNull was returning FALSE for a cell formated as a date but with the contents deleted from the cell.
Here equal to vbNullString evaluated to TRUE.
Again it seems that using IsNull, IsBlank or equal to vbNullString is a matter of using the right one in the right situation.
Don’t forget “Not” and “IsEmpty” to make things even more interesting.
(ps- the trackback on your post is from a splog.)
HTH,
JP