From c07a08d88bc4ea7fccf90bcc08b6e2264cf0f78c Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Sat, 30 May 2020 10:43:41 +0800
Subject: [PATCH] Support mssql

---
 dialects/mssql/create.go | 95 ++++++++++++++++++++++++++++++++++++++++
 dialects/mssql/mssql.go  | 28 ++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 dialects/mssql/create.go

diff --git a/dialects/mssql/create.go b/dialects/mssql/create.go
new file mode 100644
index 00000000..4aecce10
--- /dev/null
+++ b/dialects/mssql/create.go
@@ -0,0 +1,95 @@
+package mssql
+
+import (
+	"reflect"
+
+	"github.com/jinzhu/gorm"
+	"github.com/jinzhu/gorm/callbacks"
+	"github.com/jinzhu/gorm/clause"
+)
+
+func Create(db *gorm.DB) {
+	if db.Statement.Schema != nil && !db.Statement.Unscoped {
+		for _, c := range db.Statement.Schema.CreateClauses {
+			db.Statement.AddClause(c)
+		}
+	}
+
+	if db.Statement.SQL.String() == "" {
+		db.Statement.AddClauseIfNotExists(clause.Insert{
+			Table: clause.Table{Name: db.Statement.Table},
+		})
+		db.Statement.AddClause(callbacks.ConvertToCreateValues(db.Statement))
+
+		db.Statement.Build("INSERT")
+		db.Statement.WriteByte(' ')
+
+		c := db.Statement.Clauses["VALUES"]
+		if values, ok := c.Expression.(clause.Values); ok {
+			if len(values.Columns) > 0 {
+				db.Statement.WriteByte('(')
+				for idx, column := range values.Columns {
+					if idx > 0 {
+						db.Statement.WriteByte(',')
+					}
+					db.Statement.WriteQuoted(column)
+				}
+				db.Statement.WriteByte(')')
+
+				if db.Statement.Schema.PrioritizedPrimaryField != nil {
+					db.Statement.WriteString(" OUTPUT INSERTED.")
+					db.Statement.WriteQuoted(db.Statement.Schema.PrioritizedPrimaryField.DBName)
+				}
+
+				db.Statement.WriteString(" VALUES ")
+
+				for idx, value := range values.Values {
+					if idx > 0 {
+						db.Statement.WriteByte(',')
+					}
+
+					db.Statement.WriteByte('(')
+					db.Statement.AddVar(db.Statement, value...)
+					db.Statement.WriteByte(')')
+				}
+			} else {
+				db.Statement.WriteString("DEFAULT VALUES")
+			}
+		}
+
+		db.Statement.WriteByte(' ')
+		db.Statement.Build("ON CONFLICT")
+	}
+
+	rows, err := db.Statement.ConnPool.QueryContext(db.Statement.Context, db.Statement.SQL.String(), db.Statement.Vars...)
+
+	if err == nil {
+		defer rows.Close()
+
+		switch db.Statement.ReflectValue.Kind() {
+		case reflect.Slice, reflect.Array:
+			for rows.Next() {
+				// for idx, field := range fields {
+				// 	values[idx] = field.ReflectValueOf(db.Statement.ReflectValue.Index(int(db.RowsAffected))).Addr().Interface()
+				// }
+
+				values := db.Statement.Schema.PrioritizedPrimaryField.ReflectValueOf(db.Statement.ReflectValue.Index(int(db.RowsAffected))).Addr().Interface()
+				if err := rows.Scan(values); err != nil {
+					db.AddError(err)
+				}
+				db.RowsAffected++
+			}
+		case reflect.Struct:
+			// for idx, field := range fields {
+			// 	values[idx] = field.ReflectValueOf(db.Statement.ReflectValue).Addr().Interface()
+			// }
+			values := db.Statement.Schema.PrioritizedPrimaryField.ReflectValueOf(db.Statement.ReflectValue).Addr().Interface()
+
+			if rows.Next() {
+				err = rows.Scan(values)
+			}
+		}
+	} else {
+		db.AddError(err)
+	}
+}
diff --git a/dialects/mssql/mssql.go b/dialects/mssql/mssql.go
index ad6782c7..35fcb484 100644
--- a/dialects/mssql/mssql.go
+++ b/dialects/mssql/mssql.go
@@ -26,10 +26,38 @@ func Open(dsn string) gorm.Dialector {
 func (dialector Dialector) Initialize(db *gorm.DB) (err error) {
 	// register callbacks
 	callbacks.RegisterDefaultCallbacks(db, &callbacks.Config{})
+	db.Callback().Create().Replace("gorm:create", Create)
 	db.ConnPool, err = sql.Open("sqlserver", dialector.DSN)
+
+	for k, v := range dialector.ClauseBuilders() {
+		db.ClauseBuilders[k] = v
+	}
 	return
 }
 
+func (dialector Dialector) ClauseBuilders() map[string]clause.ClauseBuilder {
+	return map[string]clause.ClauseBuilder{
+		"LIMIT": func(c clause.Clause, builder clause.Builder) {
+			if limit, ok := c.Expression.(clause.Limit); ok {
+				if limit.Offset > 0 {
+					builder.WriteString("OFFSET ")
+					builder.WriteString(strconv.Itoa(limit.Offset))
+					builder.WriteString("ROWS")
+				}
+
+				if limit.Limit > 0 {
+					if limit.Offset == 0 {
+						builder.WriteString(" OFFSET 0 ROWS")
+					}
+					builder.WriteString(" FETCH NEXT ")
+					builder.WriteString(strconv.Itoa(limit.Limit))
+					builder.WriteString(" ROWS ONLY")
+				}
+			}
+		},
+	}
+}
+
 func (dialector Dialector) Migrator(db *gorm.DB) gorm.Migrator {
 	return Migrator{migrator.Migrator{Config: migrator.Config{
 		DB:                          db,