Added NewAlias

README-tw.md

@@ -369,11 +369,14 @@ rushia.NewQuery("Users").WhereValue("Username", "=", "YamiOdymel").Exists()
 
 ### 表格別名
 
-有些時候需要幫表格建立別名（或建立子指令時），透過 `As` 就能做到。
+`As` 能夠替目前的查詢語句賦予表格別名，通常會應用在子查詢。若是在表格加入（JOIN）或是一般場景，則可以使用 `NewAlias`。
 
 ```go
-rushia.NewQuery("Users").As("U").Select()
-// 等效於：SELECT * FROM Users AS U
+rushia.NewQuery(NewQuery("Users").Select()).As("Result").WhereValue("Username", "=", "YamiOdymel").Select())
+// 等效於：SELECT * FROM (SELECT * FROM Users) AS Result WHERE Username = ?
+
+rushia.NewQuery(rushia.NewAlias("UserFriendRelationships", "relations")).Where("relations.ID", "=", 5).Select()
+// 等效於： SELECT * FROM UserFriendRelationships AS relations WHERE ID = ?
 ```
 
 ### 執行生指令

README.md

@@ -371,11 +371,14 @@ rushia.NewQuery("Users").WhereValue("Username", "=", "YamiOdymel").Exists()
 
 ### Table alias
 
-When creating a sub query or table joins, you might need `As` to assign an alias to a table.
+`As` assign an alias to the query, it's useful if you are creating a sub query. In a joining or common scenario, use `NewAlias` instead.
 
 ```go
-rushia.NewQuery("Users").As("U").Select()
-// Equals: SELECT * FROM Users AS U
+rushia.NewQuery(NewQuery("Users").Select()).As("Result").WhereValue("Username", "=", "YamiOdymel").Select())
+// Equals: SELECT * FROM (SELECT * FROM Users) AS Result WHERE Username = ?
+
+rushia.NewQuery(rushia.NewAlias("UserFriendRelationships", "relations")).Where("relations.ID", "=", 5).Select()
+// Equals: SELECT * FROM UserFriendRelationships AS relations WHERE ID = ?
 ```
 
 ### Raw Query

query_test.go

@@ -752,6 +752,16 @@ func TestRawWhere(t *testing.T) {
 	assertParams(assert, []interface{}{"YamiOdymel"}, params)
 }
 
+//=======================================================
+// As
+//=======================================================
+
+func TestAs(t *testing.T) {
+	assert := assert.New(t)
+	query, _ := Build(NewQuery(NewAlias("Products", "p")).Select())
+	assertEqual(assert, "SELECT * FROM Products AS p", query)
+}
+
 //=======================================================
 // Distinct
 //=======================================================

rushia.go

@@ -2,6 +2,7 @@ package rushia
 
 import (
 	"errors"
+	"fmt"
 	"reflect"
 )
 
@@ -195,6 +196,11 @@ func NewExpr(query string, params ...interface{}) *Expr {
 	}
 }
 
+// NewAlias creates an alias for a table.
+func NewAlias(table string, alias string) string {
+	return fmt.Sprintf("%s AS %s", table, alias)
+}
+
 // Build builds the Query.
 func Build(q *Query) (query string, params []interface{}) {
 	query += q.padSpace(q.buildQuery())