The FullTextSqlQuery class is part of the Enterprise Search Query Object Model and is used to perform content queries using (amongst other things) managed properties and search scopes.

This functionality is used by the OOTB search components, but obviously you can use it for your own purposes too, and when doing so you will need to build up your own query statement, which is very much like (note: the syntax is like RDBMS SQL but certainly not the same), the RDBMS SQL query syntax.

The Enterprise Search SQL Syntax, supports the use of 2 full-text predicates which can be used as part of your WHERE clause, namely FREETEXT and CONTAINS.

This post is about the CONTAINS predicate and sumarises the syntactical forms I found actually worked, the documentation is misleading and some of the examples on the MSDN page, just don’t work, and cause the following exception when calling the Execute() method.

Exception: Your query is malformed. Please rephrase your query.

Microsoft.Office.Server.Search.Query.QueryMalformedException: Your query is malformed. Please rephrase your query.
at Microsoft.Office.Server.Search.Query.FullTextSqlQuery.Execute()