comphead commented on code in PR #12142:
URL: https://github.com/apache/datafusion/pull/12142#discussion_r1730134229
##########
datafusion/expr/src/logical_plan/builder.rs:
##########
@@ -1331,7 +1331,17 @@ pub fn validate_unique_names<'a>(
})
}
-/// Union two logical plans.
+/// Union two [`LogicalPlan`]s.
+///
+/// Constructs the UNION plan, but does not perform type-coercion. Therefore
the
+/// subtree expressions will not be properly typed until the optimizer pass.
+///
+/// If a properly typed UNION plan is needed, refer to
[`TypeCoercionRewriter::coerce_union`]
+/// or alternatively, merge the union input schema using
[`coerce_union_schema`] and
+/// apply the expression rewrite with [`coerce_plan_expr_for_schema`].
+///
+/// [`TypeCoercionRewriter::coerce_union`]:
https://docs.rs/datafusion-optimizer/latest/datafusion_optimizer/analyzer/type_coercion/struct.TypeCoercionRewriter.html#method.coerce_union
Review Comment:
👍
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For queries about this service, please contact Infrastructure at:
us...@infra.apache.org
---------------------------------------------------------------------
To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org
For additional commands, e-mail: github-h...@datafusion.apache.org
