Added supporte to choose the fields in the select stmt generation

sqlgen/sqlgen.go

@@ -10,11 +10,17 @@ import (
 	"strings"
 )
 
-func Select(obj interface{}) string {
+func Select(obj interface{}, args...[]string) string {
 	t := reflect.TypeOf(obj)
-	fieldNames := fieldNames(t)
+	var sql string
+
+	if len(args) != 0 {
+		sql = fmt.Sprintf("select %s from %s", strings.Join(args[0], ", "), t.Name())
+	} else {
+		fieldNames := fieldNames(t)
+		sql = fmt.Sprintf("select %s from %s", strings.Join(fieldNames, ", "), t.Name())
+	}
 
-	sql := fmt.Sprintf("select %s from %s", strings.Join(fieldNames, ", "), t.Name())
 	return strings.ToLower(sql)
 }
 

sqlgen/sqlgen_test.go

@@ -33,7 +33,7 @@ func TestPrepraredFields(t *testing.T) {
 	}
 }
 
-func TestGenerateSelectFromStruct(t *testing.T) {
+func TestGenerateSelectAllFieldsFromStruct(t *testing.T) {
 	var p Person
 	expected := "select id, name, age from person"
 	got := Select(p)
@@ -42,6 +42,16 @@ func TestGenerateSelectFromStruct(t *testing.T) {
 	}
 }
 
+func TestSelectOneFieldFromStruct(t *testing.T) {
+	var p Person
+	expected := "select name from person"
+	got := Select(p, []string{"name"})
+
+	if expected != got {
+		t.Errorf(`SELECT generation for %q. Was expecting "%s", got "%s".`, reflect.TypeOf(p), expected, got)
+	}
+}
+
 func TestGenerateInsertFromStruct(t *testing.T) {
 	var p Person
 	expected := "insert into person (id, name, age) values (?, ?, ?)"