本文介紹了在SQL Server 2014中將(文本)行轉換為列的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
我正在嘗試捕獲特定組的行，然后將它們轉換為命名腳本標頭的列。
這是一個數據示例：
FORMULAS | INSTRUCTIONS
----------+----------------------------------------------------
AF100120 | **ACETALDEHYDE WARNING - USE APPROPRIATE CAUTION**
AF100120 | ADD REMAINING ITEMS
AF100120 | DISSOLVE ITEMS 1-2 IN 3
AF100120 | IF HEAT USED, COOL TO ROOM TEMPERATURE
AF100120 | MIX UNTIL HOMOGENEOUS
AF100120 | MIXING TIMES VARY WITH BATCH SIZE
AF100997 | 1) DISSOLVE THYMOL CRYSTALS IN ETHYL ALCOHOL. MIX WELL.
AF100997 | 2) ADD REMAINING ITEMS AND MIX UNTIL UNIFORM.
AF100997 | 3) FILTER IF NOT CLEAR
此腳本的所需輸出為：
FORMULAS | INSTRUCTION #1 |INSTRUCTION #2 | INSTRUCTION #3 |INSTRUCTION #4 |INSTRUCTION #5|INSTRUCTION #6
AF100120 |**ACETALDEHYDE..| ADD REMAINING.| DISSOLVE ITEM. |IF HEAT USED.. |MIX UNTIL H |MIXING TIM...
AF100997 |1) DISSOLVE THYM| 2) ADD REMAINI| FILTER IF NOT | NULL |NULL |NULL
如果有人能幫我編寫代碼，我將不勝感激：
SELECT *
FROM
(SELECT
A.FormulaId AS FORMULAS,
CAST(B.Instruction AS NVARCHAR(100)) AS [INSTRUCTIONS]
FROM
Formulas AS A
LEFT JOIN
FormulaProcedures AS B ON A.FormulaId = B.FormulaId
WHERE
B.ProcedureType = 3
AND PhaseType = 2
AND YEAR(A.VersionDate) >= '2018'
AND A.PrimaryVersion = 1
AND A.FormulaId IN('AF100120', 'AF100997')
GROUP BY
A.FormulaId, CAST(B.Instruction AS NVARCHAR(100))
) AS SourceTable
PIVOT
(MAX([INSTRUCTIONS])
FOR [INSTRUCTIONS] IN ([INSTRUCTION #1], [INSTRUCTION #2],
[INSTRUCTION #3], [INSTRUCTION #4],
[INSTRUCTION #5], [INSTRUCTION #6])) AS PivotTable;
謝謝！
推薦答案
可以使用動態透視包含ROW_NUMBER()函數，其值按formulas按instructions列分組，以便在迭代分析函數時對列名進行編號：
DECLARE @cols AS NVARCHAR(MAX), @query AS NVARCHAR(MAX)
SELECT @cols =
STUFF((SELECT DISTINCT ',' + QUOTENAME(CONCAT('formulas',[rn])) AS formulas
FROM
(
SELECT f.*,
ROW_NUMBER() OVER
(PARTITION BY [formulas] ORDER BY [instructions]) AS rn
FROM [Formulas_Tab] f
) ff
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)')
,1,1,'');
SET @query =
N'SELECT *
FROM
(
SELECT f.*,
CONCAT(''formulas'',
ROW_NUMBER() OVER
(PARTITION BY [formulas] ORDER BY [instructions])) AS rn
FROM [Formulas_Tab] f
) ff
PIVOT
(
MAX([instructions]) FOR [rn] IN (' + @cols + N')
) p '
EXEC sp_executesql @query;
Demo
如果您安裝的數據庫的版本是2017+，那么您將使用STRING_AGG()函數來確定@cols變量為
SELECT @cols =
SELECT STRING_AGG(QUOTENAME(CONCAT('formulas', [ rn ])), ',') AS formulas
FROM
(
SELECT DISTINCT ROW_NUMBER() OVER
( PARTITION BY [ formulas ] ORDER BY [ instructions ]) AS rn
FROM [ Formulas_Tab ] f
) ff
這篇關于在SQL Server 2014中將(文本)行轉換為列的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，
