Case Sensitivity

Query language keywords such as SELECT, NULL, DATE, and <TRACE> are case-insensitive. Identifiers such as attribute names, method names, and path expressions are case-sensitive.

In terms of query string and region entry matching, if you want to perform a case-insensitive search on a particular field, you can use the Java String class toUpperCase and toLowerCase methods in your query. For example:
SELECT entry.value FROM /exampleRegion.entries entry WHERE entry.value.toUpperCase LIKE '%BAR%'
SELECT * FROM /exampleRegion WHERE foo.toLowerCase LIKE '%bar%'