// GET: StoreManager/Create
public IActionResult Create()
{
ViewData["ArtistID"] = new SelectList(_context.Set <Artist>(), "ArtistID", "ArtistID");
ViewData["GenreID"] = new SelectList(_context.Set <Genre>(), "GenreID", "GenreID");
return(View());
}
//查询歌手表
public ActionResult SearchTableArtist()
{
//Linq表达式
var artistList1 = from x in db.Set <Artist>() select x;
//Lambda表达式
var artists1 = db.Set <Artist>().Select(x => x);
//Linq单条件查询
artistList1 = from c in db.Set <Artist>()
where c.Name.Contains("AC")//等效SQL：where name like "%AC%"
select c;
//Linq多条件查询
artistList1 = from c in db.Set <Artist>()
where (c.Name.Contains("AC") && c.ArtistId == 5)//等效SQL：where name like "%AC%"
select c;
//Linq多表查询
var query1 = from a in db.Set <Album>()
join b in db.Set <Genre>() on a.Genre.GenreId equals b.GenreId
select a;
//Linq多表，带条件查询
query1 = from x in db.Set <Album>()
join y in db.Artists on x.Artist.ArtistId equals y.ArtistId
where y.Name.Contains("ac")
select x;
//查询Album、Artist，指定列表ArtistName、AlbumTitle、Price
//多表并指定列
var albumAndArtist = from a in db.Set <Album>()
join b in db.Set <Artist>() on a.Artist.ArtistId equals b.ArtistId
select new
{
ArtistName = b.Name,
AlbumTitle = a.Title,
Price = a.Price
};
//Lambda单条件查询
artists1 = db.Set <Artist>().Select(x => x).Where(x => x.Name.Contains("AC"));
//Lambda多条件查询
artists1 = db.Set <Artist>()
.Where(x => x.Name.Contains("AC") && x.ArtistId == 5);
//Lambda多表查询
var query2 = db.Set <Album>()
.Join(db.Set <Genre>(), x => x.Genre.GenreId, y => y.GenreId, (x, y) => x);
//查询Album、Artist，指定列表ArtistName、AlbumTitle、Price，只取第一条数据
var query3 = db.Set <Album>()
.Join(db.Set <Artist>(), a => a.Artist.ArtistId, b => b.ArtistId, (a, b) => a)
.Select(a => (new { title = a.Title, price = a.Price, artist = a.Artist.Name }))
//.OrderBy(x => x.price);//升序排序
//.OrderByDescending(x=>x.price);//降序排序
.FirstOrDefault(); //取默认第一条数据
return(View());
}
