Greenhouse Gas Operator Definition
Comparison Operators
The Operator Definition and the Search Value fields allow you to enter specific search criteria to further refine the information that is being selected. The Operator Definition field allows you to specify the scope of the search value that you are entering under the Search Value option. It is predicated on the type of column that you selected: character, number or date. For character columns, you are allowed to search for all values containing the value, beginning with or equal to the value. Each of these operator definitions gives you a greater specificity for the search. For number values, you have equal to, greater than/equal to, less than, and less than/equal to. For date values, you have starting from, equal to, and ending with.
You will only be allowed to enter Search Values that are appropriate to the type of the column. For instance, if you entered a character value in a number column, that value will be rejected by the search engine. If you are unsure about column type, clicking on the column name will take you to a page detailing the column.
In database terms, the Search Options are really "comparison operators". What they do is compare the database column value against the search value that you've entered from the search. Based on the comparison, the database will either accept the row for processing or it will reject the row. Explanations for each operator are given below:
OPERATOR | USAGE | RETRIEVAL EFFICIENCY |
---|---|---|
Equal to | The database will only return rows where the column value is equal to the search value. | Very Good |
Not Equal to | The database will only return rows where the column value is NOT equal to the search value. | Very Good |
Beginning with | The database will only return rows where the start of column value is equal to the search value. A comparison is done, character by character, up to the last character entered for the search value. | Very Good |
Less than/Equal to | The database will only return rows where the column value is equal to or less than the search value. | Very Good |
Greater than/Equal to | The database will only return rows where the column value is equal to or greater than the search value. | Very Good |
Less than | The database will only return rows where the column value is less than the search value. | Very Good |
Greater than | The database will only return rows where the column value is greater than the search value. | Very Good |
Containing | For Character fields only. The database will only return rows where the search value is contained within the column value. As an example if the search value entered is "ABC" and the column value is "CCABCDD" then the row will be accepted. Using the same search value of "ABC" if the column value was "AABBCC" then the row will be rejected. | Poor |
In | A very powerful operator for Character fields only. Instead of a single search value, the user can enter multiple search values, each separated by a comma. The database will only return rows where the column value is equal to one of search values. As an example if the search value entered is "CCAA, AABB, CCAB" and the column value is "CCAB" then the row will be accepted. Using the same search value of "CCAA, AABB, CCAB" if the column value was "CCBB" then the row will be rejected. | Good |
Not In | The Opposite of the "In" operator. Instead of a single search value, the user can enter multiple search values, each separated by a comma. The database will only return rows where the column value is not equal to one of search values. As an example if the search value entered is "CCAA, AABB, CCAB" and the column value is "CCAB" then the row will be rejected. Using the same search value of "CCAA, AABB, CCAB" if the column value was "CCBB" then the row will be accepted. | Average |
Between | Instead of a single search value, the user enters a starting and an ending search value, separated by the literal "AND". The database will only return rows where the column value is equal to or greater than the starting search value and less than or equal to the ending search value. As an example if the search value entered is "60085 and 60087" and the column value is "60085" then the row will be accepted. Using the same search value of "60085 and 60087" if the column value was "60088" then the row will be rejected. To aid the user, a pop-up window is displayed which will automatically insert the "AND" literal. | Good |