How to Search for a Null Value: Difference between revisions

From The New York Botanical Garden
Jump to navigation Jump to search
No edit summary
No edit summary
Line 1: Line 1:
Or how to search for nothing.
Or how to search for nothing.


It is not uncommon to want to search for records with a null value in a particular field. Which search string you use will depend on what it is that you [[don’t]] want to find. '''In EMu, the exclamation mark specifies NOT.''' Thus:
It is not uncommon to want to search for records with a null value in a particular field. Which search string you use will depend on what it is that you '''don’t''' want to find. '''In EMu, the exclamation mark specifies NOT.''' Thus:


'''!+''' in an attachment field will return all records where there is no attachment in that field.
'''!+''' in an attachment field will return all records where there is no attachment in that field.

Revision as of 16:51, 24 October 2022

Or how to search for nothing.

It is not uncommon to want to search for records with a null value in a particular field. Which search string you use will depend on what it is that you don’t want to find. In EMu, the exclamation mark specifies NOT. Thus:

!+ in an attachment field will return all records where there is no attachment in that field.

!* in any field will return records where there is no value in a field.

Keep in mind that these searches take longer than searches using complete words.

Example

Find all Lecythis specimens without images:

File:ClipCapIt-151123-162641.PNG
File:ClipCapIt-151123-162658.PNG