Updated Query from Multi Tables (markdown)

2881099
2025-12-12 21:33:08 +08:00
parent c1e0d8ca49
commit d2c0609ccc

@@ -78,47 +78,21 @@ fsql.Select<Topic, Category, CategoryType>()
> Experience: [One-to-many, only the last record is taken from the associated table ](https://github.com/dotnetcore/FreeSql/issues/430)
## 3. WithSql
3、WithoutJoin
fsql.Select<Order, Product, User>()
.InnerJoin((o, p, u) => o.UserId == u.Id)
.LeftJoin((o, p, u) => o.ProductId == p.Id)
.WithoutJoin(t2: !includeProductInfo)
.ToList((o, p, u) => new OrderDetailDto
{
OrderId = o.Id,
OrderNo = o.OrderNo,
Username = u.Username, // User (T3) 始终 JOIN可直接引用
ProductName = includeProductInfo ? p.Name : "N/A"
});
```csharp
fsql.Select<Topic, Category, CategoryType>()
.WithSql(
"select * from Topic where id=@id1",
"select * from Category where id=@id2",
null, //Do not set the SQL corresponding to CategoryType
new { id1 = 10, id2 = 11, id3 = 13 }
)
.LeftJoin((a,b,c) => a.CategoryId == b.Id)
.LeftJoin((a,b,c) => b.ParentId == c.Id)
.ToList();
//SELECT ...
//FROM ( select * from Topic where id=@id1 ) a
//LEFT JOIN ( select * from Category where id=@id2 ) b ON a.`CategoryId` = b.`Id`
//LEFT JOIN `CategoryType` c ON b.`ParentId` = c.`Id`
```
> Tip: `ISelect.ToSql` can be used with `WithSql`
> v3.2.666 [UnionAll Query](%E8%81%94%E5%90%88%E6%9F%A5%E8%AF%A2)、[WithTempQuery + FromQuery Nested Query](%e5%b5%8c%e5%a5%97%e6%9f%a5%e8%af%a2)
> v3.2.666 WithMemory Query using memory data
```csharp
var list = new List<Topic>();
list.Add(new Topic { ... });
list.Add(new Topic { ... });
fsql.Select<Topic>()
.WithMemory(list)
.ToList()
//SELECT a.`Id`, a.`Clicks`, a.`CategoryId`, a.`Title`, a.`CreateTime`
//FROM (
// SELECT ...
// UNION ALL
// SELECT ...
//) a
```
// includeProductInfo = true: SQL JOIN Product
// includeProductInfo = false: SQL will not JOIN Product, ProductName will be "N/A"
## 4. SQL join table