diff --git a/pkg/expression/constant.go b/pkg/expression/constant.go
index c39684f3332c3..6bc3a8b45423c 100644
--- a/pkg/expression/constant.go
+++ b/pkg/expression/constant.go
@@ -32,7 +32,7 @@ import (
 
 var _ base.HashEquals = &Constant{}
 
-// NewOne stands for a number 1.
+// NewOne stands for an unsigned number 1.
 func NewOne() *Constant {
 	retT := types.NewFieldType(mysql.TypeTiny)
 	retT.AddFlag(mysql.UnsignedFlag) // shrink range to avoid integral promotion
@@ -44,7 +44,18 @@ func NewOne() *Constant {
 	}
 }
 
-// NewZero stands for a number 0.
+// NewSignedOne stands for a signed number 1.
+func NewSignedOne() *Constant {
+	retT := types.NewFieldType(mysql.TypeTiny)
+	retT.SetFlen(1)
+	retT.SetDecimal(0)
+	return &Constant{
+		Value:   types.NewDatum(1),
+		RetType: retT,
+	}
+}
+
+// NewZero stands for an unsigned number 0.
 func NewZero() *Constant {
 	retT := types.NewFieldType(mysql.TypeTiny)
 	retT.AddFlag(mysql.UnsignedFlag) // shrink range to avoid integral promotion
@@ -56,6 +67,17 @@ func NewZero() *Constant {
 	}
 }
 
+// NewSignedZero stands for a signed number 0.
+func NewSignedZero() *Constant {
+	retT := types.NewFieldType(mysql.TypeTiny)
+	retT.SetFlen(1)
+	retT.SetDecimal(0)
+	return &Constant{
+		Value:   types.NewDatum(0),
+		RetType: retT,
+	}
+}
+
 // NewUInt64Const stands for constant of a given number.
 func NewUInt64Const(num int) *Constant {
 	retT := types.NewFieldType(mysql.TypeLonglong)
diff --git a/pkg/planner/core/expression_rewriter.go b/pkg/planner/core/expression_rewriter.go
index 8024d545cc614..42306c205d43c 100644
--- a/pkg/planner/core/expression_rewriter.go
+++ b/pkg/planner/core/expression_rewriter.go
@@ -1103,9 +1103,9 @@ func (er *expressionRewriter) handleExistSubquery(ctx context.Context, planCtx *
 			return v, true
 		}
 		if (row != nil && !v.Not) || (row == nil && v.Not) {
-			er.ctxStackAppend(expression.NewOne(), types.EmptyName)
+			er.ctxStackAppend(expression.NewSignedOne(), types.EmptyName)
 		} else {
-			er.ctxStackAppend(expression.NewZero(), types.EmptyName)
+			er.ctxStackAppend(expression.NewSignedZero(), types.EmptyName)
 		}
 	}
 	return v, true
diff --git a/tests/integrationtest/r/executor/issues.result b/tests/integrationtest/r/executor/issues.result
index d69b1e6072883..90fbd3efcd6d0 100644
--- a/tests/integrationtest/r/executor/issues.result
+++ b/tests/integrationtest/r/executor/issues.result
@@ -1006,3 +1006,6 @@ select from_unixtime( if(col2 >9999999999, col2/1000, col2), '%Y-%m-%d %H:%i:%s'
 result
 2024-09-03 00:00:00
 2024-09-03 00:00:00
+select ((exists (select 1)) * -5) as c1;
+c1
+-5
diff --git a/tests/integrationtest/t/executor/issues.test b/tests/integrationtest/t/executor/issues.test
index ee07ec984db0f..87d8cf0a424dc 100644
--- a/tests/integrationtest/t/executor/issues.test
+++ b/tests/integrationtest/t/executor/issues.test
@@ -767,3 +767,6 @@ explain analyze select * from pt where val = 126 order by id limit 100;  # expec
 CREATE TABLE test_55837 (col1 int(4) NOT NULL, col2 bigint(4) NOT NULL, KEY col2_index (col2));
 insert into test_55837 values(0,1725292800),(0,1725292800);
 select from_unixtime( if(col2 >9999999999, col2/1000, col2), '%Y-%m-%d %H:%i:%s') as result from test_55837;
+
+# TestIssue56641
+select ((exists (select 1)) * -5) as c1;
\ No newline at end of file