Remove alias in Union

datafusion/expr/src/logical_plan/builder.rs

@@ -958,7 +958,6 @@ pub fn union_with_alias(
     Ok(LogicalPlan::Union(Union {
         inputs,
         schema: union_schema,
-        alias,
     }))
 }
 

datafusion/expr/src/logical_plan/plan.rs

@@ -1285,8 +1285,6 @@ pub struct Union {
     pub inputs: Vec<Arc<LogicalPlan>>,
     /// Union schema. Should be the same for all inputs.
     pub schema: DFSchemaRef,
-    /// Union output relation alias
-    pub alias: Option<String>,
 }
 
 /// Creates an in memory table.

datafusion/expr/src/utils.rs

@@ -546,13 +546,10 @@ pub fn from_plan(
         LogicalPlan::Extension(e) => Ok(LogicalPlan::Extension(Extension {
             node: e.node.from_template(expr, inputs),
         })),
-        LogicalPlan::Union(Union { schema, alias, .. }) => {
-            Ok(LogicalPlan::Union(Union {
-                inputs: inputs.iter().cloned().map(Arc::new).collect(),
-                schema: schema.clone(),
-                alias: alias.clone(),
-            }))
-        }
+        LogicalPlan::Union(Union { schema, .. }) => Ok(LogicalPlan::Union(Union {
+            inputs: inputs.iter().cloned().map(Arc::new).collect(),
+            schema: schema.clone(),
+        })),
         LogicalPlan::Distinct(Distinct { .. }) => Ok(LogicalPlan::Distinct(Distinct {
             input: Arc::new(inputs[0].clone()),
         })),

datafusion/optimizer/src/filter_push_down.rs

@@ -607,11 +607,7 @@ fn optimize(plan: &LogicalPlan, mut state: State) -> Result<LogicalPlan> {
             // sort is filter-commutable
             push_down(&state, plan)
         }
-        LogicalPlan::Union(Union {
-            inputs: _,
-            schema,
-            alias: _,
-        }) => {
+        LogicalPlan::Union(Union { inputs: _, schema }) => {
             // union changing all qualifiers while building logical plan so we need
             // to rewrite filters to push unqualified columns to inputs
             let projection = schema

datafusion/optimizer/src/limit_push_down.rs

@@ -172,11 +172,7 @@ fn limit_push_down(
             )?))
         }
         (
-            LogicalPlan::Union(Union {
-                inputs,
-                alias,
-                schema,
-            }),
+            LogicalPlan::Union(Union { inputs, schema }),
             Ancestor::FromLimit {
                 skip: ancestor_skip,
                 fetch: Some(ancestor_fetch),
@@ -205,7 +201,6 @@ fn limit_push_down(
                 .collect::<Result<_>>()?;
             Ok(LogicalPlan::Union(Union {
                 inputs: new_inputs,
-                alias: alias.clone(),
                 schema: schema.clone(),
             }))
         }

datafusion/optimizer/src/projection_push_down.rs

@@ -392,11 +392,7 @@ fn optimize_plan(
                 schema: a.schema.clone(),
             }))
         }
-        LogicalPlan::Union(Union {
-            inputs,
-            schema,
-            alias,
-        }) => {
+        LogicalPlan::Union(Union { inputs, schema }) => {
             // UNION inputs will reference the same column with different identifiers, so we need
             // to populate new_required_columns by unqualified column name based on required fields
             // from the resulting UNION output
@@ -438,7 +434,6 @@ fn optimize_plan(
             Ok(LogicalPlan::Union(Union {
                 inputs: new_inputs.iter().cloned().map(Arc::new).collect(),
                 schema: Arc::new(new_schema),
-                alias: alias.clone(),
             }))
         }
         LogicalPlan::SubqueryAlias(SubqueryAlias { input, alias, .. }) => {