LeonidChistov commented on PR #3163:
URL: https://github.com/apache/calcite/pull/3163#issuecomment-1521214338

   @zinking 
   
   I mean that old approach works wrong when field names from left hand side 
and right hide collide:
   
   ```
   SELECT * FROM DEPT 
   WHERE DEPTNO > 10 AND EXISTS (SELECT 1 FROM EMP WHERE DEPTNO = EMP.DEPTNO)
   ```
   If we improve it to generate query like 
   
   ```
   SELECT * FROM DEPT 
   WHERE DEPTNO > 10 AND EXISTS (SELECT 1 FROM EMP WHERE DEPT.DEPTNO = 
EMP.DEPTNO)
   ```
   then everything will be OK.
   
   But my point is that it is not so simple to do this improvement. Initially I 
didn't understand at all how to do it, but now I have another Draft Pull 
Request that does required things: https://github.com/apache/calcite/pull/3175/.
   
   But I have concern that new code is complicated and thus more error prone.
   


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