Hello, fellows, long time no see ~ Here i want to fire a discussion about the SQL implicit type coercion, a required feature for SQL production but missed for Flink SQL for a long time ~
SQL implicit type coercion is very useful for these cases: - the inter-operation within builtin SQL operators, like binary arithmetic operations (PLUS, MINOUS and so on), binary comparison, IN, CASE WHEN, SET operator (UNION, INTERSECT ..) - the built in functions type coercion for input parameters - the SQL INSERT source that target connector row type when are are row elements type mismatch - the compatibility with other popular DB engines, like MySQL/Hive/PostgreSQL and so on And so much voices for a long time from the user mailing list. I have created a FLIP WIKI here [1] and wait for your appreciate suggestions ~ Thanks again for all you awesome guys and hope that we can have a conclusion for the type coercion rules (the matrix) for Flink SQL soon. [1] https://cwiki.apache.org/confluence/display/FLINK/FLIP-154%3A+SQL+Implicit+Type+Coercion Best, Danny Chan
