I realized today, after browsing many google results, that it is illicit to use a "null" value as a parameter of a where clause. Because null is considered to be unknown, two null values compared to each other are not considered to be equal. In expressions using arithmetic operators, if any of the operands is null, the result is null as well. Details can be found here : https://stackoverflow.com/questions/36992184/sqlcommand-createparameter-value-dbnull-value-not-returning-results So it was obvious that my simple C# sample would not work and it had actually nothing to do with the Cloudera ODBC driver. ... View more