SelectWithUnionQuery (children 1) ExpressionList (children 1) SelectQuery (children 1) ExpressionList (children 2) Function overlay (children 1) ExpressionList (children 3) Literal \'Spark SQL\' Function materialize (children 1) ExpressionList (children 1) Literal \'_\' Function materialize (children 1) ExpressionList (children 1) Literal UInt64_6 Function overlayUTF8 (children 1) ExpressionList (children 3) Literal \'Spark SQL和CH\' Function materialize (children 1) ExpressionList (children 1) Literal \'_\' Function materialize (children 1) ExpressionList (children 1) Literal UInt64_6