左外部結合 DefaultIfEmptyメソッドを使う var q = from item1 in Tbl_FOO.Where(p => a.CD_FOO == param) join item2 in Tbl_Hoge on a.CD_AAA equals item2.CD_AAA into a from item2 in a.DefaultIfEmpty() NVL的な ？？演算子で変換する select new LIST…