在sql server中的select*表查询中显示拆分结果

我正在使用下面的语句-如何获得预期的结果

select t1.StudentName, t1.Email, s.items Module
from Student t1
outer apply dbo.Split(t1.Module, ',') s

当前

 StudentName | Email      | Module
    S1       | s1@uni.com | Math
    S1       | s1@uni.com | English
    S1       | s1@uni.com | Science

预期的

StudentName | Email       | Module
                          | Math
S1          | s1@uni.com  | English
                          | Science

---

注意：使用SQL Server 2017

基于预期结果，您需要

案例

表达式：

select (case when s.items = 'English' then t1.StudentName end) as StudentName ,
       (case when s.items = 'English' then t1.Email end) as Email,
       s.items Module
from Student t1 outer apply 
     dbo.Split(t1.Module, ',') s;

With cte as (select t1.StudentName, t1.Email, s.value, row_number() OVER (PARTITION BY StudentName,email ORDER BY StudentName) rn
from Student t1
outer apply STRING_SPLIT(t1.Module, ',') s)
select StudentName,email, value from (select case when c1.rn = c2.rn and c1.rn = 1 then c1.StudentName
                                           else null
                                           end as StudentName,
                                      case when c1.rn = c2.rn and c1.rn = 1 then c1.email 
                                           else null
                                           end as email,
                                      case when c1.value = c2.value then c1.value
                                           else null
                                           end as value
                               from cte c1 join cte c2
                               on c1.StudentName = c2.StudentName
                               and c1.email = c2.email)t
where t.value is not null

---

如果您希望特定行应填充

StudentName&Email

，而不考虑

模块

，则可以使用

行号（）
 您可以使用如下查询（可能需要更改
idx
列以匹配拆分函数）：

SQL小提琴：

如果要垂直对齐输出，可以尝试下一个示例。请注意，使用
STRING\u SPLIT（）
时，输出行的顺序可能是任意的，并且不能保证顺序与输入字符串中的子字符串的顺序匹配

表:

CREATE TABLE Data (
   StudentName varchar(100), 
   Email varchar(100),
   Module varchar(100)
)
INSERT INTO Data 
   (StudentName, Email, Module)
VALUES
   ('S1', 's1@uni.com', 'Math,English,Science'),
   ('S2', 's1@uni.com', 'Math,English,Science,Grammar,Sports'),
   ('S3', 's1@uni.com', 'Math,English,Science,Sports'),
   ('S4', 's1@uni.com', 'Math')

声明：

SELECT 
  CASE WHEN (s.Cnt / 2 + 1) = s.Rn THEN d.StudentName END AS StudentName, 
  CASE WHEN (s.Cnt / 2 + 1) = s.Rn THEN d.Email END AS Email, 
  s.Module
FROM Data d
OUTER APPLY (
   SELECT 
      [value] AS Module, 
      COUNT(*) OVER (ORDER BY (SELECT NULL)) AS Cnt,
      ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS Rn
   FROM STRING_SPLIT(d.Module, ',') 
) s

结果:

-----------------------------------
StudentName Email           Module
-----------------------------------
                            Math
S1          s1@uni.com      English
                            Science
                            Math
                            English
S2          s1@uni.com      Science
                            Grammar
                            Sports
                            Math
                            English
S3          s1@uni.com      Science
                            Sports
S4          s1@uni.com      Math

我在SQL Server 2017中尝试过这一点

With cte as (select t1.StudentName, t1.Email, s.value, row_number() OVER (PARTITION BY StudentName,email ORDER BY StudentName) rn
from Student t1
outer apply STRING_SPLIT(t1.Module, ',') s)
select StudentName,email, value from (select case when c1.rn = c2.rn and c1.rn = 1 then c1.StudentName
                                           else null
                                           end as StudentName,
                                      case when c1.rn = c2.rn and c1.rn = 1 then c1.email 
                                           else null
                                           end as email,
                                      case when c1.value = c2.value then c1.value
                                           else null
                                           end as value
                               from cte c1 join cte c2
                               on c1.StudentName = c2.StudentName
                               and c1.email = c2.email)t
where t.value is not null

有没有一种没有硬编码的方法？谢谢你的回答