Question

我有一张桌子，如下：

   Type_id name  Comments
   -------------------
   61        a     aa        
   62        a     Test2
   62        b     bb        
   63        c     cc   
   63        b     bb  
   63        c     bb       
   64        c     cc

现在，我要选择如下结果集：

  Type_id name  Comments
   -------------------
   61        a     aa        
   62        a     Test2
             b     bb        
   63        c     cc   
             b     bb 
             c     bb        
   64        c     cc

如果有多个值，重复的Type_id应该显示一个空字符串。我尝试使用CASE语句，但运气不佳。

这是我尝试过的查询：

      select 
        case when Type_id = 61 then  'Cell1' 
        when Type_id = 62 then  'Cell2' 
        when Type_id = 63 then  'Cell3' 
            else ''
        end as Type_id,
        name,
        Comments
     FROM 
        TBL
     where 
        CATEGORY_ID = 120
        order by Type_id

谁能帮助我。预先感谢。

Answer 1

我结合了LAG和CASE来解决：

# version 2
def schedule_single_scoring(
    submission: Submission,
    scoring_specification: ScoringSpecification) -> SubmissionScore:
    """multiline docstrings are present"""

# version 3
def schedule_single_scoring(submission: Submission, scoring_specification:
        ScoringSpecification) -> SubmissionScore:

Answer 2

这是我的版本

--temp data
if object_id('tempdb..#x') is not null drop table #x
CREATE TABLE #x(type_id INT, name VARCHAR(1), comments VARCHAR(20))
INSERT INTO #x(type_id, name, comments) VALUES
  ( 61,        'a',     'aa'),        
   ( 62,        'a',     'Test2'),
   ( 62,        'b',     'bb'),        
   ( 63,        'c',     'cc'),   
   ( 63,        'b',     'bb'),  
    (63,        'c',     'bb'),       
    (64,        'c',     'cc')

--query
SELECT CASE WHEN type_id=LAG(type_id,1,0) OVER(ORDER BY type_id) THEN NULL ELSE type_id END AS 'type_id', 
        name, comments
FROM #x

输出

type_id name    comments
61      a        aa
62      a        Test2
NULL    b        bb
63      c        cc
NULL    b        bb
NULL    c        bb
64      c        cc

如果您没有请求者声明的LAG，则

if object_id('tempdb..#x') is not null drop table #x
CREATE TABLE #x(type_id INT, name VARCHAR(1), comments VARCHAR(20))
INSERT INTO #x(type_id, name, comments) VALUES
  ( 61,        'a',     'aa'),        
   ( 62,        'a',     'Test2'),
   ( 62,        'b',     'bb'),        
   ( 63,        'c',     'cc'),   
   ( 63,        'b',     'bb'),  
    (63,        'c',     'bb'),       
    (64,        'c',     'cc')


if object_id('tempdb..#a') is not null drop table #a
SELECT x.*,
       ROW_NUMBER() OVER(PARTITION BY x.type_id ORDER BY x.type_id) AS 'id_count'
INTO #a
FROM #x AS x

SELECT CASE WHEN a.id_count>1 THEN NULL ELSE a.type_id END AS 'type_id',
     a.name, a.comments
FROM #a AS a

Answer 3

select 
    case when row_number() -- only return 1st value
              over (partition by Type_id
                    order by name) = 1
         then cast(Type_id as varchar(10))
         else ''
    end as Type_id,
    name,
    Comments
FROM 
    TBL
where 
    CATEGORY_ID = 120
order by Type_id, name -- same order by used in ROW_NUMBER

SQL-Case语句删除重复的列

3 个答案: