Sql 将三行（带空）中的数据合并为一行

我有三张桌子：

Profile
  -ProfileID
  -FirstName
  -LastName

ProfilePhoneNumber
  -ProfileID
  -PhoneNumberID

PhoneNumber
  -PhoneNumberID
  -PhoneNumberTypeID
  -Number

ProfilePhoneNumber是Profile和PhoneNumber之间的一个简单桥接表

我想查询特定的电话号码类型并返回一行。我希望能够接受空值，因为不是所有人都有所有类型的电话号码

以下是我当前的查询：

SELECT
      p.FirstName
    , p.LastName
    , bpn.Number as BusinessPhoneNumber
    , mpn.Number as MobilePhoneNumber
FROM Profile p
LEFT JOIN ProfilePhoneNumber ppn ON p.ProfileID = ppn.ProfileID
LEFT JOIN PhoneNumber bpn ON ppn.PhoneNumberID = bpn.PhoneNumberID AND bpn.PhoneNumberTypeID = '1'
LEFT JOIN PhoneNumber mpn ON ppn.PhoneNumberID = mpn.PhoneNumberID AND mpn.PhoneNumberTypeID = '2'
WHERE p.ProfileID = '123'

这始终有效，但会返回三行，因为Profile 123有三个电话号码，因此查询会为每个电话号码返回一行

如果我将其更改为PhoneNumber上的内部联接，我只能返回一行，但只有在被查询的配置文件具有我要查询的所有PhoneNumberTypeID类型的情况下

如何返回一个允许空的行？

如果您提供一些数据样本和预期输出，我将稍后更新查询

到目前为止，这会有帮助吗

SELECT
      p.FirstName
    , p.LastName
    , Max(bpn.Number) as BusinessPhoneNumber
    , Max(mpn.Number) as MobilePhoneNumber

FROM Profile p
    LEFT JOIN ProfilePhoneNumber ppn on p.ProfileID = ppn.ProfileID
        LEFT JOIN PhoneNumber bpn on ppn.PhoneNumberID 
         = bpn.PhoneNumberID AND bpn.PhoneNumberTypeID = '1'
        LEFT JOIN PhoneNumber mpn on ppn.PhoneNumberID 
         = mpn.PhoneNumberID AND mpn.PhoneNumberTypeID = '2'

WHERE p.ProfileID = '123'
group by p.FirstName, p.LastName;

---

如果每个配置文件每种类型有一部手机，则您可以：

使用内部连接查询将配置文件与每个电话类型匹配 使用LEFT JOIN query将配置文件与上述配置文件匹配 DDL：

查询：

SELECT Profile.FirstName, Profile.LastName, BusPhone.Number AS BusPhoneNumber, MobPhone.Number AS MobPhoneNumber
FROM profile
LEFT JOIN (
    SELECT ProfileID, Number
    FROM profilephonenumber
    INNER JOIN phonenumber ON profilephonenumber.PhoneNumberID = phonenumber.PhoneNumberID
    WHERE PhoneNumberTypeID = 1
) AS BusPhone ON Profile.ProfileID = BusPhone.ProfileID
LEFT JOIN (
    SELECT ProfileID, Number
    FROM profilephonenumber
    INNER JOIN phonenumber ON profilephonenumber.PhoneNumberID = phonenumber.PhoneNumberID
    WHERE PhoneNumberTypeID = 2
) AS MobPhone ON Profile.ProfileID = MobPhone.ProfileID

输出：

+------+-----+--------+--------+ |FirstName | LastName |总线电话号码|移动电话号码| +------+-----+--------+--------+ |用户| 1 | 0800-U1BUS |空| |用户| 2 | 0800-U2BUS | 0800-U2MOB| |用户| 3 | 0800-U3BUS | 0800-U3MOB| +------+-----+--------+--------+

---

将其更改为“选择不同”是否可以解决您的问题？如果没有，当有人有多个电话号码时，你想如何选择显示哪一个商业或移动电话号码？@APH问得好。我不确定Select distinct是否能在这里工作，或者我是否需要作弊并做TOP 1。我相信我可以添加更多的条件来提高选择性，但现在我的重点是返回一个允许空的行。示例数据、SQLFIDLE、预期输出将很有帮助……谢谢@MrSimpleMind。我将对此进行研究。我建议所有三个左连接都是相等缩进的-它们当前缩进的方式表明第二个和第三个是第一个的子查询-它们不是。在一些场景中测试这一点，但这似乎是可行的。我将这个语句包装在一个外部联接中，因为它嵌套在一个更大的查询中。

SELECT Profile.FirstName, Profile.LastName, BusPhone.Number AS BusPhoneNumber, MobPhone.Number AS MobPhoneNumber
FROM profile
LEFT JOIN (
    SELECT ProfileID, Number
    FROM profilephonenumber
    INNER JOIN phonenumber ON profilephonenumber.PhoneNumberID = phonenumber.PhoneNumberID
    WHERE PhoneNumberTypeID = 1
) AS BusPhone ON Profile.ProfileID = BusPhone.ProfileID
LEFT JOIN (
    SELECT ProfileID, Number
    FROM profilephonenumber
    INNER JOIN phonenumber ON profilephonenumber.PhoneNumberID = phonenumber.PhoneNumberID
    WHERE PhoneNumberTypeID = 2
) AS MobPhone ON Profile.ProfileID = MobPhone.ProfileID

-- Sample data.
declare @Profile as Table ( ProfileId Int Identity, FirstName VarChar(10), LastName VarChar(10) );
insert into @Profile ( FirstName, LastName ) values
  ( 'Alice', 'Aardvark' ), ( 'Bob', 'Bear' ), ( 'Cindy', 'Cat' );

declare @PhoneNumber as Table ( PhoneNumberId Int Identity, PhoneNumberTypeId Int, Number VarChar(10) );
insert into @PhoneNumber ( PhoneNumberTypeId, Number ) values
  ( 1, '1111111111' ), ( 2, '1112221111' ), ( 1, '1113331111' ), ( 2, '2222222222' );

declare @ProfilePhoneNumber as Table ( ProfileId Int, PhoneNumberId Int );
insert into @ProfilePhoneNumber ( ProfileId, PhoneNumberId ) values
  ( 1, 1 ), ( 1, 2 ),
  ( 2, 3 ),
  ( 3, 4 );

-- Dump the sample data.
select *
  from @Profile as P left outer join
    @ProfilePhoneNumber as PPN on PPN.ProfileId = P.ProfileId left outer join
    @PhoneNumber as PN on PN.PhoneNumberId = PPN.PhoneNumberId;

-- Do the deed.
with ExtendedPhoneNumbers as (
  select ProfileId, PhoneNumberTypeId, Number
    from @ProfilePhoneNumber as PPN inner join
      @PhoneNumber as PN on PN.PhoneNumberId = PPN.PhoneNumberId )
  select P.FirstName, P.LastName,
    EPNB.Number as BusinessPhoneNumber,
    EPNM.Number as MobilePhoneNumber
  from @Profile as P left outer join
    ExtendedPhoneNumbers as EPNB on P.ProfileID = EPNB.ProfileID and EPNB.PhoneNumberTypeId = 1 left outer join
    ExtendedPhoneNumbers as EPNM on P.ProfileID = EPNM.ProfileID and EPNM.PhoneNumberTypeId = 2
  where P.ProfileId = 2; -- Comment out the WHERE clause to see all profiles.