1. A method of processing streaming data, the method comprising: initializing, by a computer processor, a stream of data for a continuous query logic (CQL) operation; identifying, by the computer processor, at least one column of interest within the stream of data, the at least one column of interest to be monitored for changes to data that occur within the at least one column of interest over a time interval; selecting, by a relation-to-stream operator, the at least one column of interest by applying the relation-to-stream operator to a SELECT list expression to select a subset of the stream of data over the time interval, the SELECT list expression comprising a parameter of the relation-to-stream operator; monitoring, by the relation-to-stream operator, changes to the data that occur within the at least one column of interest over the time interval by applying the relation-to-stream operator to the column of interest; determining, by the relation-to-stream operator, that at least one value from the at least one column of interest has changed based at least in part on applying a clause associated with the relation-to-stream operator on the column of interest, the clause detecting that the at least one value in the at least one column of interest has changed within the time interval; and in response to determining that the at least one value of the at least one column of interest has changed, outputting the at least one value that has changed in the at least one column of interest that occurs within the time interval using the CQL operation.