feat(planner): support expression alias

src/planner_v2/binder/expression/mod.rs

@@ -47,4 +47,13 @@ impl BoundExpression {
             BoundExpression::BoundCastExpression(expr) => expr.base.alias.clone(),
         }
     }
+
+    pub fn set_alias(&mut self, alias: String) {
+        match self {
+            BoundExpression::BoundColumnRefExpression(expr) => expr.base.alias = alias,
+            BoundExpression::BoundConstantExpression(expr) => expr.base.alias = alias,
+            BoundExpression::BoundReferenceExpression(expr) => expr.base.alias = alias,
+            BoundExpression::BoundCastExpression(expr) => expr.base.alias = alias,
+        }
+    }
 }

src/planner_v2/binder/query_node/bind_select_node.rs

@@ -124,9 +124,18 @@ impl Binder {
             sqlparser::ast::SelectItem::UnnamedExpr(expr) => {
                 expr_binder.bind_expression(expr, result_names, result_types)
             }
-            sqlparser::ast::SelectItem::ExprWithAlias { .. } => todo!(),
-            sqlparser::ast::SelectItem::Wildcard(_) => todo!(),
-            sqlparser::ast::SelectItem::QualifiedWildcard(_, _) => todo!(),
+            sqlparser::ast::SelectItem::ExprWithAlias { expr, alias } => {
+                let mut expr = expr_binder.bind_expression(expr, result_names, result_types)?;
+                expr.set_alias(alias.to_string());
+                if let Some(last_name) = result_names.last_mut() {
+                    *last_name = alias.to_string();
+                }
+                Ok(expr)
+            }
+            sqlparser::ast::SelectItem::Wildcard(..)
+            | sqlparser::ast::SelectItem::QualifiedWildcard(..) => Err(BindError::Internal(
+                "wildcard should expand before bind select item".to_string(),
+            )),
         }
     }
 }

tests/slt/select.slt

@@ -28,3 +28,12 @@ select *, t1.* from t1;
 ----
 1 4 0 1 4 0
 2 5 1 2 5 1
+
+
+# TODO: use alias function to verify output column names
+onlyif sqlrs_v2
+query III
+select t.v1 as a, v2 as b from t1 as t;
+----
+1 4
+2 5