fix dashboard SQL placeholders

internal/storage/active_reconcile.go

@@ -666,11 +666,11 @@ GROUP BY d.sys_origin, d.country_code`, statTimezone, statTimezone, sysOrigin, s
 }
 
 func inPlaceholders(count int) string {
-	return "(" + placeholders(count, 1) + ")"
+	return "(" + strings.TrimRight(strings.Repeat("?,", count), ",") + ")"
 }
 
 func inStringPlaceholders(count int) string {
-	return "(" + placeholders(count, 1) + ")"
+	return inPlaceholders(count)
 }
 
 func stringArgs(values []string) []interface{} {

internal/storage/placeholders_test.go

@@ -0,0 +1,25 @@
+package storage
+
+import "testing"
+
+func TestInPlaceholdersUsesScalarList(t *testing.T) {
+	tests := []struct {
+		name  string
+		count int
+		want  string
+	}{
+		{name: "single", count: 1, want: "(?)"},
+		{name: "multiple", count: 3, want: "(?,?,?)"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := inPlaceholders(tt.count); got != tt.want {
+				t.Fatalf("inPlaceholders(%d) = %q, want %q", tt.count, got, tt.want)
+			}
+			if got := inStringPlaceholders(tt.count); got != tt.want {
+				t.Fatalf("inStringPlaceholders(%d) = %q, want %q", tt.count, got, tt.want)
+			}
+		})
+	}
+}