This is kind of in the scope of implicit type coercion which is supported in CALCITE-2302.
For sql dialect that does not support implicit type coercion, strip explicit cast is a mistake. I think this can be seen as a bug and we should log an issue to fix. But just like you said, if we support it for every sql dialect, it would be a huge work, we should think of a flexible way. Best, Danny Chan 在 2019年8月28日 +0800 PM4:56，Soma Mondal <[email protected]>，写道： > Hi Julian, > > After some further analysis, it seems that the mandatory cast is only > required in SOME cases for BigQuery. > Please see attached my analysis for Hive, MySQL, Netezza and Oracle. > > https://drive.google.com/open?id=1GJ_VuDY7GQS-aPbWf4EKj73dYCqaRaEqPTjmXLkPW_g > > I'm thinking of having the dialect intercept this and check the specific > conditions (specified in the sheet above) and decide whether or not to > remove the cast. > > Regards, > Soma > > > On Mon, 26 Aug 2019 at 22:29, Julian Hyde <[email protected]> wrote: > > > I might be mistaken, but disabling stripCastFromString() for some dialects > > and not others doesn’t sound like it’s solving the root cause of the > > problem. > > > > Julian > > > > > > > On Aug 26, 2019, at 7:49 AM, Soma Mondal <[email protected]> > > wrote: > > > > > > Hi Julian, > > > > > > 2 tests failed when I made the stripCastFromString() no-op. > > > > > > 1. > > > > > > testDb2DialectSelectQueryWithGroup > > > 2. > > > > > > testSelectQueryWithGroup > > > > > > Above tests pretty much do the same thing and basically strip the cast > > from > > > String literal something like this: > > > > > > Expected: > > > > > > SELECT COUNT(*), SUM(employee_id) > > > > > > FROM foodmart.reserve_employee > > > > > > WHERE hire_date > '2015-01-01' AND (position_title = 'SDE' OR > > > position_title = 'SDM') > > > > > > GROUP BY store_id, position_title > > > > > > But with no-op we get this: > > > > > > SELECT COUNT(*), SUM(employee_id) > > > > > > FROM foodmart.reserve_employee > > > > > > WHERE hire_date > CAST('2015-01-01' AS TIMESTAMP(0)) AND (position_title > > = > > > 'SDE' OR position_title = 'SDM') > > > > > > GROUP BY store_id, position_title > > > > > > Can I go ahead and make changes where calls to stripCastFromString() will > > > be skipped for specific dialects? > > > > > > Regards, > > > > > > Soma > > > > > > > > > On Fri, 23 Aug 2019 at 16:02, Soma Mondal <[email protected]> > > > wrote: > > > > > > > Hello, > > > > > > > > We have a REL which has this information > > > > select * from employee where employee_id = cast('12' as float); > > > > > > > > but Calcite removes the CAST from the STRING literal('12' in our case). > > > > select * from employee where employee_id = '12'; > > > > > > > > There are dialects which needs explicit casting in the above case and we > > > > need to maintain the CAST in our dialect. > > > > Calcite removes the cast in SqlImplementor's stripCastFromString() > > > > method. I would like to understand why Calcite removes the CAST and > > shall > > > > we go ahead and make the changes in Calcite to maintain the CAST. > > > > > > > > Thanks & Regards, > > > > Soma Mondal > > > > > > > >
