From f0a88b68a9710342e6260a1befad2cf3d44c292a Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Sat, 3 Mar 2018 14:29:07 +0800
Subject: [PATCH] Add limit, order builder

---
 dialects/common/sqlbuilder/limit.go | 26 +++++++++++++++++++++++++
 dialects/common/sqlbuilder/order.go | 30 +++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 dialects/common/sqlbuilder/limit.go
 create mode 100644 dialects/common/sqlbuilder/order.go

diff --git a/dialects/common/sqlbuilder/limit.go b/dialects/common/sqlbuilder/limit.go
new file mode 100644
index 00000000..519cdf95
--- /dev/null
+++ b/dialects/common/sqlbuilder/limit.go
@@ -0,0 +1,26 @@
+package sqlbuilder
+
+import (
+	"fmt"
+
+	"github.com/jinzhu/gorm"
+)
+
+// BuildLimitCondition build limit condition
+func BuildLimitCondition(tx *gorm.DB) chan *Builder {
+	limitChan := make(chan *Builder)
+
+	go func() {
+		builder := &Builder{}
+		if limit := tx.Statement.Limit; limit.Limit != nil {
+			builder.SQL.WriteString(fmt.Sprintf(" LIMIT %d", *limit.Limit))
+
+			if limit.Offset != nil {
+				builder.SQL.WriteString(fmt.Sprintf(" OFFSET %d", *limit.Offset))
+			}
+		}
+		limitChan <- builder
+	}()
+
+	return limitChan
+}
diff --git a/dialects/common/sqlbuilder/order.go b/dialects/common/sqlbuilder/order.go
new file mode 100644
index 00000000..57241623
--- /dev/null
+++ b/dialects/common/sqlbuilder/order.go
@@ -0,0 +1,30 @@
+package sqlbuilder
+
+import "github.com/jinzhu/gorm"
+
+// BuildOrderCondition build order condition
+func BuildOrderCondition(tx *gorm.DB) chan *Builder {
+	orderChan := make(chan *Builder)
+
+	go func() {
+		builder := &Builder{}
+
+		if orderBy := tx.Statement.OrderBy; len(orderBy) > 0 {
+			builder.SQL.WriteString(" ORDER BY ")
+			for i, by := range orderBy {
+				if i > 0 {
+					builder.SQL.WriteString(", ")
+				}
+				if str, ok := by.(string); ok {
+					builder.SQL.WriteString(str)
+				} else {
+					buildCondition(tx, by, builder)
+				}
+			}
+		}
+
+		orderChan <- builder
+	}()
+
+	return orderChan
+}