[GitHub] [calcite] danny0405 commented on issue #1299: [CALCITE-3100] cast(? as DATE) won't work with PreparedStatement

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danny0405 commented on issue #1299: [CALCITE-3100] cast(? as DATE) won't work with PreparedStatement
URL: https://github.com/apache/calcite/pull/1299#issuecomment-509122864
 
 
   @jinxing64 
   >SqlValidator infers the "type" of SqlDynamicParam by the "type" of CAST. And during the optimization, such a CAST will be regarded as redundant and get simplified/peeled.
   
   `SqlValidatorImpl` did use the operand0 type of the `SqlDynamicParam` directly, and it's the sql-to-rel conversion that create a `RexDynamicParam` with the correct type (not the optimization phrase).
   
   We can see that the `RexDynamicParam` has the correct data type, but the java type factory has an `int` type for sql `DATE` and `TIMESTAMP` type. [3] 
   
   @yuqi1129 Although cast to `string.class` type first can solve this problem, i still think the intermediate type should depend on what the type the JDBC `DataContext` returns. 
   
   [1] https://github.com/apache/calcite/blob/046f9f4e2e3c779e4e2e61946d67a0dc124f7f72/core/src/main/java/org/apache/calcite/sql/fun/SqlCastFunction.java#L107
   [2] https://github.com/apache/calcite/blob/046f9f4e2e3c779e4e2e61946d67a0dc124f7f72/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java#L3006
   [3] https://github.com/apache/calcite/blob/046f9f4e2e3c779e4e2e61946d67a0dc124f7f72/core/src/main/java/org/apache/calcite/jdbc/JavaTypeFactoryImpl.java#L179
   
   

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