我不知道如何解释我需要什么,但首先是数据:
Table 1
District
-1
3
2
1
3
Table 2
ID ID_Name
1 Main 1
2 Main 2
3 Main 3
如何连接表以使其看起来像这样?
District
-1
Main 3
Main 2
Main 1
Main 3
我假设第二列为此命名为Name
,但您可以使用COALESCE
和LEFT JOIN
来做到这一点:
Select Coalesce(T2.Name, Str(T1.District)) As District
From Table1 T1
Left Join Table2 T2 On T1.District = T2.Id
假设表 2 有
Table 2
ID col2
1 Main 1
2 Main 2
3 Main 3
您可以使用左联接
select table1.Distric, table2.col2
from table1
left join table2 on table1.dictrict = t2.ID
order by table2 col2
您可以使用左连接:
Select coalesce(t2.col, t1.District) from table1 t1
left join table2 t2 on t1.District = t2.Id