C＃のLINQラムダは、私はMSQLクエリのカウンターパートを探しています参加し、構文

Question

を選択

var query = persons.JOIN(address,per = person.addressId,add = addressId 
    (per,add) => 
    new Persons{ 
       addressDescription = add.addressDescription, 
       PersonId = per.PersonId, 
       PersonFirstName = per.PersonFirstName 
       PersonLastName = per.PersonLastName}) 

個別に割り当てずPersons.addressDescriptionを移入する方法はありますPersonsの他のプロパティ？ Personsにさらに10の特性があると想像してください。

私のようなループの使用を控えたいと思います：

foreach(Person person in PersonList) 
{ 
    foreach(Address address in AddressList) 
    { 
    if(person.addressId == address.addressId){ 
     person.addressDescription = address.addressDescription 
    } 
    } 
} 

Answer 1

var query = persons.join(address, 
    per = person.addressId, 
    add = addressId 
    (per,add) => 
    { 
     per.addressDescription = add.addressDescription; 
     return per; 
    }); 

Answer 2

var id = 1; 
var query = database.Posts // your starting point - table in the "from" statement 
    .Join(database.Post_Metas, // the source table of the inner join 
     post => post.ID,  // Select the primary key (the first part of the "on" clause in an sql "join" statement) 
     meta => meta.Post_ID, // Select the foreign key (the second part of the "on" clause) 
     (post, meta) => new { Post = post, Meta = meta }) // selection 
    .Where(postAndMeta => postAndMeta.Post.ID == id); // where statement