1. A method of operating on database queries, comprising: receiving values that specify a parameterized input query in a first database query language, wherein the parameterized input query includes one or more parameters that are assigned values to execute the parameterized input query in the first database query language; using a computer for determining a plurality of randomized input queries in the first database query language by substituting a selection of random parameter values for the one or more parameters in the parameterized input query, wherein for each randomized input query a corresponding random-argument list identifies the one or more random parameter values for the one or more parameters; determining a plurality of randomized output queries in a second database query language by translating the randomized input queries in the first database query language into corresponding randomized output queries in the second database query language, wherein for each randomized output query the random-argument list of a corresponding randomized input query identifies the one or more random parameter values for the one or more parameters; determining from the randomized output queries a plurality of filtered output queries in the second database query language by replacing each occurrence of the one or more parameter values in the random-argument lists with a parameter placeholder, wherein for each filtered output query a corresponding parameter-order list identifies a corresponding parameter for each parameter placeholder; and selecting a representative filtered output query from the filtered output queries by evaluating a likelihood of the representative filtered output query relative to the filtered output queries, wherein the representative filtered output query defines a parameterized output query in the second database query language and its parameter-order list identifies a corresponding one or more parameters that are assigned values to execute the parameterized output query in the second database query language.