update

嵌套查询.md

@@ -28,13 +28,47 @@ FROM (
 WHERE (a.[rownum] = 1)
 ```
 
-场景2：分组查询嵌套
+场景2：嵌套查询 + Join
+
+WithTempQuery + From\<T2\> 或 FromQuery\<ISelect\<T2\>\> 可实现无限联表
+
+```c#
+fsql.Select<User1>()
+    .Where(a => a.Id < 1000)
+    .WithTempQuery(a => new
+    {
+        item = a,
+        rownum = SqlExt.RowNumber().Over().PartitionBy(a.Nickname).OrderBy(a.Id).ToValue()
+    })
+    .Where(a => a.rownum == 1)
+    //.From<UserExt>() //普通联表
+    .FromQuery(fsql.Select<UserExt>().Where(b => b.Id > 0)) //子查询联表
+    //.FromQuery(fsql.Select<UserExt, UserGroup, xxx>().WithTempQuery((a,b,c) => new { ... })) //子多表查询联表
+    .InnerJoin((a, b) => a.item.Id == b.UserId)
+    .ToList((a, b) => new
+    {
+        user = a.item,
+        rownum = a.rownum,
+        userext = b
+    });
+```
+
+```sql
+SELECT ... 
+FROM ( 
+    SELECT a.[Id], a.[Nickname], row_number() over( partition by a.[Nickname] order by a.[Id]) [rownum] 
+    FROM [User1] a ) a 
+INNER JOIN (SELECT a.[UserId], a.[Remark] 
+    FROM [TwoTablePartitionBy_UserExt] a 
+    WHERE (a.[UserId] > 0)) b ON a.[Id] = b.[UserId] 
+WHERE (a.[rownum] = 1)
+```
+
+场景3：分组查询嵌套
 
 待补充..
 
-场景3：嵌套查询 + Join
-
-待补充..
+---
 
 ## 子表Exists