sql - MSSQL 将连接顺序按空值保留到最后，而如果所有空值按 ID 排序

Question

我有这个 mssql 查询

SELECT TOP 50 [id], [title], [url], [icon], linkstats.visits 
FROM [websites] LEFT OUTER JOIN [linkstats] ON websites.id=linkstats.lid AND linkstats.code=@country 
WHERE (([country] = @country OR [country]= 'all') AND 
      ([hot] = @hot)) 
ORDER BY linkstats.visits DESC

我想按空值排序到最后，如果都是空值，那么按 ID 排序怎么做？！

Answer 1

采用CASE

SELECT TOP 50 [id], [title], [url], [icon], linkstats.visits 
FROM [websites] LEFT OUTER JOIN [linkstats] ON websites.id=linkstats.lid AND linkstats.code=@country 
WHERE (([country] = @country OR [country]= 'all') AND 
      ([hot] = @hot)) 
ORDER BY CASE WHEN linkstats.lid IS NULL THEN 1 ELSE 0 END,
         linkstats.visits DESC