Question

我正在尝试检索有关我们环境中服务器的信息，并且我需要检索信息的某些服务器不存在。例如，ServerD，ServerF，ServerJ和ServerN不在我查询的表中。

SELECT Server, Active, Location
    FROM Repository.dbo.Servers
    WHERE Server IN (
    'ServerA',
    'ServerB',
    'ServerC',
    'ServerD',
    'ServerE',
    'ServerF',
    'ServerG',
    'ServerH',
    'ServerI',
    'ServerJ',
    'ServerK',
    'ServerL',
    'ServerM',
    'ServerN',
    'ServerO'
    )
    ORDER BY ServerName

这些是此查询的结果，但我想要一些不存在的服务器（ServerD，ServerF，ServerJ和ServerN）的值，例如NULL等。

ServerA N   Springfield, IL
ServerB Y   Cleveland, OH
ServerC Y   Springfield, IL
ServerE Y   Cleveland, OH
ServerG Y   Cleveland, OH
ServerH Y   Memphis, TN
ServerI Y   Springfield, IL
ServerK N   Cleveland, OH
ServerL Y   Cleveland, OH
ServerM Y   Springfield, IL
ServerO Y   Memphis, TN

如何在T-SQL中完成？例如，我希望返回类似于此的内容：

    ServerA N   Springfield, IL
    ServerB Y   Cleveland, OH
    ServerC Y   Springfield, IL
    ServerD NULL
    ServerE Y   Cleveland, OH
    ServerF NULL
    ServerG Y   Cleveland, OH
    ServerH Y   Memphis, TN
    ServerI Y   Springfield, IL
    ServerJ NULL
    ServerK N   Cleveland, OH
    ServerL Y   Cleveland, OH
    ServerM Y   Springfield, IL
    ServerN NULL
    ServerO Y   Memphis, TN

Answer 1

Per your comments you have some table that does have all the servers. Use that table and left join the servers table.

SELECT t1.Server, t2.Active, t2.Location
FROM TheTableThatHasAllServers t1
LEFT JOIN Repository.dbo.Servers t2 on t1.server = t2.server
WHERE t1.Server IN (
'ServerA',
'ServerB',
'ServerC',
'ServerD',
'ServerE',
'ServerF',
'ServerG',
'ServerH',
'ServerI',
'ServerJ',
'ServerK',
'ServerL',
'ServerM',
'ServerN',
'ServerO'
)
ORDER BY t1.ServerName

T-SQL处理没有结果

1 个答案: