diff --git a/enginetest/queries/queries.go b/enginetest/queries/queries.go
index d52e6dad94..83918c7222 100644
--- a/enginetest/queries/queries.go
+++ b/enginetest/queries/queries.go
@@ -8719,6 +8719,14 @@ from typestable`,
 			{1, 0, 3, 2},
 		},
 	},
+	{
+		Query: "select * from mytable where i > '-0.5';",
+		Expected: []sql.Row{
+			{1, "first row"},
+			{2, "second row"},
+			{3, "third row"},
+		},
+	},
 }
 
 var KeylessQueries = []QueryTest{
diff --git a/sql/index_builder.go b/sql/index_builder.go
index 3f1f290b9b..3254c08862 100644
--- a/sql/index_builder.go
+++ b/sql/index_builder.go
@@ -64,6 +64,14 @@ func ceil(val interface{}) interface{} {
 		return math.Ceil(v)
 	case decimal.Decimal:
 		return v.Ceil()
+	case string:
+		dec, err := decimal.NewFromString(v)
+		if err != nil {
+			return v
+		}
+		return ceil(dec)
+	case []byte:
+		return ceil(string(v))
 	default:
 		return v
 	}
@@ -77,6 +85,14 @@ func floor(val interface{}) interface{} {
 		return math.Floor(v)
 	case decimal.Decimal:
 		return v.Floor()
+	case string:
+		dec, err := decimal.NewFromString(v)
+		if err != nil {
+			return v
+		}
+		return floor(dec)
+	case []byte:
+		return floor(string(v))
 	default:
 		return v
 	}