From 7b14c48574ecf32768eb1567569588b5b8f28838 Mon Sep 17 00:00:00 2001
From: James Cor <james@dolthub.com>
Date: Wed, 12 Mar 2025 13:29:35 -0700
Subject: [PATCH 1/2] don't erase dual table projection

---
 enginetest/queries/queries.go      | 13 +++++++++++++
 sql/analyzer/optimization_rules.go |  7 +++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/enginetest/queries/queries.go b/enginetest/queries/queries.go
index 78391e3f97..ac1dbee062 100644
--- a/enginetest/queries/queries.go
+++ b/enginetest/queries/queries.go
@@ -10171,6 +10171,18 @@ from typestable`,
 			{2},
 		},
 	},
+	{
+		Query: "select ''",
+		Expected: []sql.Row{
+			{""},
+		},
+	},
+	{
+		Query: "select '' from dual",
+		Expected: []sql.Row{
+			{""},
+		},
+	},
 
 	{
 		Query: "select @@sql_mode = 1",
@@ -10206,6 +10218,7 @@ from typestable`,
 			{"     └─ name: "},
 		},
 	},
+
 }
 
 var KeylessQueries = []QueryTest{
diff --git a/sql/analyzer/optimization_rules.go b/sql/analyzer/optimization_rules.go
index 9d53294a9b..bd60bf99f3 100644
--- a/sql/analyzer/optimization_rules.go
+++ b/sql/analyzer/optimization_rules.go
@@ -15,7 +15,8 @@
 package analyzer
 
 import (
-	"strings"
+	"github.com/dolthub/go-mysql-server/memory"
+"strings"
 
 	"github.com/dolthub/go-mysql-server/sql"
 	"github.com/dolthub/go-mysql-server/sql/expression"
@@ -43,7 +44,9 @@ func eraseProjection(ctx *sql.Context, a *Analyzer, node sql.Node, scope *plan.S
 	return transform.Node(node, func(node sql.Node) (sql.Node, transform.TreeIdentity, error) {
 		project, ok := node.(*plan.Project)
 		if ok {
-			if project.Schema().CaseSensitiveEquals(project.Child.Schema()) {
+			projSch := project.Schema()
+			childSch := project.Child.Schema()
+			if projSch.CaseSensitiveEquals(childSch) && !childSch.Equals(memory.DualTableSchema.Schema) {
 				a.Log("project erased")
 				return project.Child, transform.NewTree, nil
 			}

From 9b1413530daf74fb48ffb361439ec6c21f704dbe Mon Sep 17 00:00:00 2001
From: jycor <jycor@users.noreply.github.com>
Date: Wed, 12 Mar 2025 20:35:04 +0000
Subject: [PATCH 2/2] [ga-format-pr] Run ./format_repo.sh to fix formatting

---
 enginetest/queries/queries.go      | 1 -
 sql/analyzer/optimization_rules.go | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/enginetest/queries/queries.go b/enginetest/queries/queries.go
index ac1dbee062..79d1192e2e 100644
--- a/enginetest/queries/queries.go
+++ b/enginetest/queries/queries.go
@@ -10218,7 +10218,6 @@ from typestable`,
 			{"     └─ name: "},
 		},
 	},
-
 }
 
 var KeylessQueries = []QueryTest{
diff --git a/sql/analyzer/optimization_rules.go b/sql/analyzer/optimization_rules.go
index bd60bf99f3..71c4c5e520 100644
--- a/sql/analyzer/optimization_rules.go
+++ b/sql/analyzer/optimization_rules.go
@@ -15,8 +15,9 @@
 package analyzer
 
 import (
+	"strings"
+
 	"github.com/dolthub/go-mysql-server/memory"
-"strings"
 
 	"github.com/dolthub/go-mysql-server/sql"
 	"github.com/dolthub/go-mysql-server/sql/expression"