Oracle Sql Query from Oracle Database to extract data

Make sure you're not including ; at the end of your sql statement

@egomm is spot on for the first thing to check.

If that's not it, please post the relevant part of your log file here so we can see what the trouble is.

@gsgoraya, If you like, you can use an Oracle non-spatial reader to read any non-spatial table you are interested in. If you want to fetch the results of a user made query, you can use any table (I alway use the DUAL table from Oracle) and after the feature type is in the cancas, you can lookup the feature type in the Navigator pane and select Parameters and Format and Select Statement. Enter the query you wish to execute (indeed, without the semicolon) in the parameter field. In the latter case you have to put an AttributeExposer transformer in the workspace naming all columns in the query result to expose them as attributes.