This help document answers the following questions about using operators on MGI query forms:
What are operators and how do they affect my query?
Operators narrow or expand the effect of a search. They usually appear on selection lists located next to a field. Examples are: begins, equals, ends, contains, less than, greater than, and so on. When a selection list is available, click the arrow beside it to see all the options available.
- Once you pick an operator, it applies to any value you enter or select for the field.
- The default operator is the one that appears when you open a query form or when you click Reset.
- Sometimes you activate an operator by clicking a check mark as, for example, when there is a NOT box next to a field (so you can exclude items from your search).
Maybe this is obvious, but what is the effect of the NOT operator?
- Clicking the NOT checkbox and selecting/entering a value (in an adjacent field) means that you want to exclude that value from your search.
- Sometimes the search turns up items that are in apparent contradiction of your intent. For example: the default setting for all MGI query forms with a Gene/Marker Symbol/Name field is to search on current symbols/names and synonyms. A gene should appear if any of its symbols (including withdrawns and synonyms) do not match the query, but some genes whose current symbol matches the query will also appear. To avoid this, change the selector to just current symbols when using the NOT operator.
Begins, equals, ends, contains, and like operators
One set of operators is comprised of begins, = (equals), ends, contains, and like; you can use these, for example, to filter what you are looking for.
- The begins operator returns only items beginning with the characters you typed in.
- The = operator finds exact matches.
- The ends operator returns items ending with the characters you typed in.
- The contains operator returns only items containing the characters you typed in.
- The like operator lets you use the percent (%) wild card within specified characters to find items (e.g., d%mit).
"Ballpark" operators (between, less than, greater than, equal to)
Another set of operators lets you establish a relationship among values: between, equal to (=), less than (<), greater than (>), less than or equal to (<=), greater than or equal to (>=), not equal to (<>). These operators are useful for defining a ballpark search region when you are entering genome coordinates on MGI query forms (Genes and Markers, Alleles, SNPs, Sequences, Gene Expression, Probes, and so on). The is null operator defines an empty list; the is not null defines a set in which the contents are unknown.
In/not in, on/not on operators
The operators in/not in or on/not on, let you specify the presence or absence of values. As examples, you can use them to include or exclude specific chromosomes when searching for SNPs annotated to mapped markers or to include/exclude developmental stages when searching for gene expression
Sometimes operators are activated by check marks: for example, clicking a NOT box puts a check mark beside a field or a list to choose items from to exclude from your search.