yangzhg opened a new issue #2834: [Proposal] Full support of set operations: add INTERSECT and EXCEPT set operators URL: https://github.com/apache/incubator-doris/issues/2834 # Description Generaly set functionality includes the below. but now doris has just support UNION & UNION ALL. ``` UNION [DISTINCT | ALL] INTERSECT [DISTINCT | ALL] EXCEPT [DISTINCT | ALL] ``` `EXCEPT ` in some systems is an alias for `MINUS` `INTERSECT` operator is used to return the results of 2 or more `SELECT` statements. However, it only returns the rows selected by all queries or data sets. If a record exists in one query and not in the other, it will be omitted from the `INTERSECT` results.  The `EXCEPT` operator is used to return all rows in the first `SELECT` statement that are not returned by the second `SELECT` statement. Each `SELECT` statement will define a dataset. The `EXCEPT` operator will retrieve all records from the first dataset and then remove from the results all records from the second dataset.  # Syntax ## INTERSECT ``` SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions] INTERSECT [DISTINCT | ALL] SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions]; ``` ## EXCEPT ``` SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions] EXCEPT|MINUS [DISTINCT | ALL] SELECT expression1, expression2, ... expression_n FROM tables [WHERE conditions]; ``` # Subtasks * Convert UnionStmt class into to SetOperationStmt, add Syntax support to sqlparser.cup * Add INTERSECT and EXCEPT support to SetOperationStmt and planner * Implements IntersectNode and ExceptNode
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