Tips on complex queries
Q0 AND Q1 OR Q2
is equivalent to (Q0 AND Q1) OR Q2 and means that condition 0 (Q0) and condition 1 (Q1) or condition 2 (Q2) have to be fulfilled for the record to be selected.
In a given database, this could allow the retrieval of 900 records (for example).
Using another groupings of the questions, like Q0 AND (Q1 OR Q2)
will lead to another selection of 30 records (for example). In this latter example, condition 1 or condition 2 has to be fulfilled at the same time than condition 0.
The use of brackets can therefore importantly change the results of the queries, even with the same original conditions.
All the opened brackets have to be closed. You may remove a question manually. For example, in:
Q0 AND Q1 AND Q2 you may remove the condition 1 and this would then look like:
Q0 AND Q2
The AND, OR, NOT could be switched. For example, you may manually change the following query:
(Q0 AND Q1) OR Q2
to (Q0 AND NOT Q1) OR Q2
or to Q0 AND Q1 AND Q2
Also keep a space before and after the AND, OR and NOT operators.
Don’t add other character than the opening and closing parenthesis ‘(‘ and ‘)’.
Wrongly written advanced queries will lead to a message stating that no records were found or that the query was wrong. Example of wrong queries:
Q0 AND Q1) AND Q2
(Q0 AND Q1 AND Q2))
Q0 AND Q1AND Q2