Add statements debug sql support.

sqlbuilder/statement.go

@@ -3,12 +3,33 @@ package sqlbuilder
 import (
 	"database/sql"
 	"github.com/sub0zero/go-sqlbuilder/types"
+	"strconv"
+	"strings"
 )
 
-type statement interface {
+type Statement interface {
 	// String returns generated SQL as string.
 	Sql() (query string, args []interface{}, err error)
 
+	DebugSql() (query string, err error)
+
 	Query(db types.Db, destination interface{}) error
 	Execute(db types.Db) (sql.Result, error)
 }
+
+func DebugSql(statement Statement) (string, error) {
+	sql, args, err := statement.Sql()
+
+	if err != nil {
+		return "", err
+	}
+
+	debugSql := sql
+
+	for i, arg := range args {
+		argPlaceholder := "$" + strconv.Itoa(i+1)
+		debugSql = strings.Replace(debugSql, argPlaceholder, ArgToString(arg), 1)
+	}
+
+	return debugSql, nil
+}