MySQL版本

您已經聲明過嘗試使用PIVOT,但是MySQL沒有PIVOT函數.在MySQL中,您需要將聚合函數與條件邏輯語句(如CASE … WHEN或類似的東西)一起使用.您還需要旋轉幾個表和幾個不同的列,這使事情變得有些復雜.似乎您還需要創建數量未知的新列,這增加了另一層復雜性.

如果您知道要在最終結果中顯示的所有列,則可以輕松鍵入此查詢的版本,如下所示：

select

p1.`SSN_ID`,

p1.Citizen_name,

p1.Company,

max(case when p2.Family_details = 'Spouse' then Family_members_name end) Spouse,

max(case when p2.Family_details = 'Child - 1' then Family_members_name end) Child1,

max(case when p2.Family_details = 'Child - 2' then Family_members_name end) Child2,

max(case when p2.Family_details = 'Child - 3' then Family_members_name end) Child3,

max(case when p2.Family_details = 'Child - 4' then Family_members_name end) Child4,

max(case when p3.Address_type = 'Present' then p3.Address end) PresentAddress,

max(case when p3.Address_type = 'Office' then p3.Address end) OfficeAddress,

max(case when p3.Address_type = 'Perement' then p3.Address end) PermAddress,

max(case when p3.PhoneNumber_type = 'Home' then p3.PhoneNumber end) HomePhone,

max(case when p3.PhoneNumber_type = 'Office' then p3.PhoneNumber end) OfficePhone,

max(case when p3.PhoneNumber_type = 'Fax' then p3.PhoneNumber end) FaxPhone

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.`SSN_ID` = p2.`SSN_ID`

left join Table_pivot_03 p3

on p1.`SSN_ID` = p3.`SSN_ID`

group by p1.`SSN_ID`,

p1.Citizen_name,

p1.Company;

基本上,您在max(case …)語句中創建了一個新列,它將顯示該值.如上所述,如果您想將未知值用作列,這會變得更加復雜.在MySQL中,您需要使用Prepared Statement,因此您可以使用動態SQL.您的代碼看起來像這樣：

SET @sql = NULL;

SET @sql1 = NULL;

SET @sql2 = NULL;

SET @sql3 = NULL;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p2.Family_details = ''',

Family_details,

''' then Family_members_name end) AS `',

Family_details, '`'

)

) INTO @sql1

FROM Table_pivot_02;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p3.Address_type = ''',

Address_type,

''' then Address end) AS `',

Address_type, '`'

)

) INTO @sql2

FROM Table_pivot_03;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p3.PhoneNumber_type = ''',

PhoneNumber_type,

''' then PhoneNumber end) AS `',

PhoneNumber_type, '`'

)

) INTO @sql3

FROM Table_pivot_03

where PhoneNumber_type <> '';

SET @sql = CONCAT('SELECT p1.`SSN_ID`,

p1.Citizen_name,

p1.Company, ', @sql1, ',', @sql2, ',', @sql3, '

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.`SSN_ID` = p2.`SSN_ID`

left join Table_pivot_03 p3

on p1.`SSN_ID` = p3.`SSN_ID`

group by p1.`SSN_ID`,

p1.Citizen_name,

p1.Company');

PREPARE stmt FROM @sql;

EXECUTE stmt;

DEALLOCATE PREPARE stmt;

在此過程中,您將創建一長串的max(case …)語句,將它們串聯在一起,然后由數據庫引擎執行.可能有更簡單的方法來獲得所需的結果,但這確實有效.在rextester上創建了一個演示以顯示代碼,這兩者都會產生結果：

+-------+--------+--------------+---------+--------+------------+------------+------------+----------------------+----------------------+------------------------+------------------+--------------------+----------------+

| Row | SSN_ID | Citizen_name | Company | Spouse | Child - 1 | Child - 2 | Child - 3 | Present | Office | Perement | Home | Office | Fax |

+-------+--------+--------------+---------+--------+------------+------------+------------+----------------------+----------------------+------------------------+------------------+--------------------+----------------+

| 1 | 12345 | John | XYZ | Mari | John Jr. 1 | John Jr. 2 | NULL | Address_John_Present | Address_John_Office | Address_John_Perement | John_Home_phone | John_Office_phone | John_FAX_phone |

| 2 | 12346 | Tom | ABC | Ken | NULL | NULL | NULL | Address_Tom_Present | Address_Tom_Office | NULL | Tom_Home_phone | Tom_Office_phone | NULL |

| 3 | 12347 | Jerry | QWER | Suzen | Jerry Jr.1 | Jerry Jr.2 | Jerry Jr.3 | NULL | Address_Jerry_Office | Address_Jerry_Perement | Jerry_Home_phone | Jerry_Office_phone | NULL |

| 4 | 12348 | Joe | PQR | NULL | Joe Jr.1 | Joe Jr.2 | NULL | Address_Joe_Present | Address_Joe_Office | Address_Josh_Perement | Joe_Home_phone | Joe_Office_phone | NULL |

| 5 | 12349 | Josh | NULL | Zoe | Josh Jr.1 | Josh Jr.2 | NULL | Address_Josh_Present | NULL | Address_Josh_Perement | Josh_Home_phone | NULL | Josh_FAX_phone |

+-------+--------+--------------+---------+--------+------------+------------+------------+----------------------+----------------------+------------------------+------------------+--------------------+----------------+

根據您的評論(每個人可能有多個電話號碼類型),您需要創建row number for each group of phone types.不幸的是,MySQL又沒有窗口功能,因此您需要使用用戶定義的變量來獲取最終的結果.當查詢PhoneNumber_type時,您將需要使用類似以下的內容：

select *

from

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

@num:= case when @group = SSN_ID and @type = PhoneNumber_type then @num +1 else if(@group := SSN_ID, 1, 1) end rn,

@group:= SSN_ID,

@type:=PhoneNumber_type

from Table_pivot_03 t

CROSS JOIN (select @num:=0, @group:=null, @type:=null) c

where t.PhoneNumber_type <> ''

order by SSN_ID, PhoneNumber_type

) as x;

這將為每個用戶和電話類型創建一個行號值.然后將其集成到動態SQL代碼中：

SET @sql = NULL;

SET @sql1 = NULL;

SET @sql2 = NULL;

SET @sql3 = NULL;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p2.Family_details = ''',

Family_details,

''' then Family_members_name end) AS `',

Family_details, '`'

)

) INTO @sql1

FROM Table_pivot_02;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p3.Address_type = ''',

Address_type,

''' then Address end) AS `',

Address_type, '`'

)

) INTO @sql2

FROM Table_pivot_03;

SELECT

GROUP_CONCAT(DISTINCT

CONCAT(

' max(case when p.PhoneNumber_type = ''',

PhoneNumber_type,

''' and rn = ', rn, ' then p.PhoneNumber end) AS `',

PhoneNumber_type, rn, '`'

)

) INTO @sql3

FROM

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

@num:= case when @group = SSN_ID and @type = PhoneNumber_type then @num +1 else if(@group := SSN_ID, 1, 1) end rn,

@group:= SSN_ID,

@type:=PhoneNumber_type

from Table_pivot_03 t

CROSS JOIN (select @num:=0, @group:=null, @type:=null) c

where t.PhoneNumber_type <> ''

order by SSN_ID, PhoneNumber_type

) as x;

SET @sql = CONCAT('SELECT p1.`SSN_ID`,

p1.Citizen_name,

p1.Company, ', @sql1, ',', @sql2, ',', @sql3, '

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.`SSN_ID` = p2.`SSN_ID`

left join Table_pivot_03 p3

on p1.SSN_ID = p3.SSN_Id

left join

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

@num:= case when @group = SSN_ID and @type = PhoneNumber_type then @num +1 else if(@group := SSN_ID, 1, 1) end rn,

@group:= SSN_ID,

@type:=PhoneNumber_type

from Table_pivot_03 t

CROSS JOIN (select @num:=0, @group:=null, @type:=null) c

where t.PhoneNumber_type <> ''''

order by SSN_ID, PhoneNumber_type

) as p

on p1.SSN_ID = p.SSN_Id

group by p1.`SSN_ID`,

p1.Citizen_name,

p1.Company');

#select @sql;

PREPARE stmt FROM @sql;

EXECUTE stmt;

DEALLOCATE PREPARE stmt;

參見另一個demo.

SQL Server版本

既然您已經說過需要SQL Server版本,那么這里就是該版本. SQL Server具有一些使操作變得更加容易的功能,包括PIVOT函數,UNPIVOT函數以及諸如row_number之類的窗口函數.這是查詢的靜態版本,其中只列出了幾列：

select SSN_ID,

Citizen_name,

Company,

Spouse, [Child - 1], [Child - 2], [Child - 3], [Child - 4]

from

(

select SSN_ID,

Citizen_name,

Company,

col,

value

from

(

select

p1.SSN_ID,

p1.Citizen_name,

p1.Company,

p2.Family_details,

p2.Family_members_name,

p3.Address_type,

p3.Address,

PhoneNumber_type = p.PhoneNumber_type + cast(p.rn as varchar(10)),

p.PhoneNumber

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.SSN_ID = p2.SSN_ID

left join Table_pivot_03 p3

on p1.SSN_ID = p3.SSN_ID

left join

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

rn = row_number() over(partition by SSN_ID, PhoneNumber_type order by SSN_ID, PhoneNumber_type)

from Table_pivot_03

where PhoneNumber_type <> ''

) p

on p1.SSN_ID = p.SSN_ID

) d

cross apply

(

select 'Family_details', Family_details, Family_members_name union all

select 'Address_type', Address_type, Address union all

select 'PhoneNumber_type', PhoneNumber_type, PhoneNumber

) c(orig, col, value)

) src

pivot

(

max(value)

for col in (Spouse, [Child - 1], [Child - 2], [Child - 3], [Child - 4])

) piv

然后,如果您需要動態sql版本,則代碼如下所示：

DECLARE @cols AS NVARCHAR(MAX),

@query AS NVARCHAR(MAX)

select @cols = STUFF((SELECT ',' + QUOTENAME(Col)

from

(

select col, ord

from

(

select

p1.SSN_ID,

p1.Citizen_name,

p1.Company,

p2.Family_details,

p2.Family_members_name,

p3.Address_type,

p3.Address,

PhoneNumber_type = p.PhoneNumber_type + cast(p.rn as varchar(10)),

p.PhoneNumber

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.SSN_ID = p2.SSN_ID

left join Table_pivot_03 p3

on p1.SSN_ID = p3.SSN_ID

left join

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

rn = row_number() over(partition by SSN_ID, PhoneNumber_type order by SSN_ID, PhoneNumber_type)

from Table_pivot_03

where PhoneNumber_type <> ''

) p

on p1.SSN_ID = p.SSN_ID

) d

cross apply

(

select 'Family_details', Family_details, Family_members_name, 1 union all

select 'Address_type', Address_type, Address, 2 union all

select 'PhoneNumber_type', PhoneNumber_type, PhoneNumber, 3

) c(orig, col, value, ord)

) d

group by col, ord

order by ord, col

FOR XML PATH(''), TYPE

).value('.', 'NVARCHAR(MAX)') ,1,1,'');

set @query = N'SELECT ' + @cols + N' from

(

select SSN_ID,

Citizen_name,

Company,

col,

value

from

(

select

p1.SSN_ID,

p1.Citizen_name,

p1.Company,

p2.Family_details,

p2.Family_members_name,

p3.Address_type,

p3.Address,

PhoneNumber_type = p.PhoneNumber_type + cast(p.rn as varchar(10)),

p.PhoneNumber

from Table_pivot_01 p1

left join Table_pivot_02 p2

on p1.SSN_ID = p2.SSN_ID

left join Table_pivot_03 p3

on p1.SSN_ID = p3.SSN_ID

left join

(

select SSN_ID, PhoneNumber_type, PhoneNumber,

rn = row_number() over(partition by SSN_ID, PhoneNumber_type order by SSN_ID, PhoneNumber_type)

from Table_pivot_03

where PhoneNumber_type <> ''''

) p

on p1.SSN_ID = p.SSN_ID

) d

cross apply

(

select ''Family_details'', Family_details, Family_members_name union all

select ''Address_type'', Address_type, Address union all

select ''PhoneNumber_type'', PhoneNumber_type, PhoneNumber

) c(orig, col, value)

) src

pivot

(

max(value)

for col in (' + @cols + N')

) p '

exec sp_executesql @query;

這是另一個demo.

總結

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