Question

如何选择少于三个单词的字符串？

例如：

id keyword
1  my name is john
2  im mike
3  david cameron
4  electra
5  goliath is my name
6  michael jordan

所以我想选择少于3个字数的关键字列，它应该是：

im mike
david cameron
electra
michael jordan

Answer 1

尝试：

select *
  from table_name
 where length(keyword) - length(replace(keyword, ' ', '')) + 1 < 3

这需要整个字符串的长度减去没有空格的字符串的长度（计算空间数），然后加一（即如果一个字符串有一个空格意味着有2个字而不是1个字），并过滤掉计算不是的任何行＆lt; 3

Answer 2

使用Jeff Moden's 8K Tally-Ho CSV splitter

create function [dbo].[DelimitedSplit8K](
   @pString varchar(8000) --WARNING!!! DO NOT USE MAX DATA-TYPES HERE!  IT WILL KILL PERFORMANCE!
  ,@pDelimiter char(1)
)
returns table with schemabinding as
return
  with E1(N) AS ( 
    select N from (values (1),(1),(1),(1),(1),(1),(1),(1),(1),(1) )E1(N)
  ),                                             --10E+1 or 10 rows
  E2(N) as (select 1 from E1 a cross join E1 b), --10E+2 or 100 rows
  E4(N) as (select 1 from E2 a cross join E2 b), --10E+4 or 10,000 rows max
  cteTally(N) as (
    select top (isnull(datalength(@pString),0))
      row_number() over (order by (select null)) 
    from E4
  ),
  start(N1) AS (--==== This returns N+1 (starting position of each "element" just once for each delimiter)
    select 1 union all
    select t.N+1 from cteTally t where substring(@pString,t.N,1) = @pDelimiter
  ),
  Len(N1,L1) as(--==== Return start and length (for use in substring)
    select s.N1,
        isnull(nullif(charindex(@pDelimiter,@pString,s.N1),0) - s.N1,8000)
    from start s
  )
  --===== Do the actual split. The ISNULL/NULLIF combo handles the length for the final element when no delimiter is found.
  select
    ItemNumber = row_number() over(order by l.N1),
    Item       = substring(@pString, l.N1, l.L1)
  from Len l
;
go

和CTE中建议的样本数据

with 
data as (
  select id,keyword from (values
     --id   keyword
     (1,  'my name is john')
    ,(2,  'im mike')
    ,(3,  'david cameron')
    ,(4,  'electra')
    ,(5,  'goliath is my name')
    ,(6,  'michael jordan')
    ,(7,  'michael   jordan')
  )data(id,keyword)
),

这个SQL

strings as (
  select
     data.id
    ,keyword
    ,s.Item
    ,s.ItemNumber
  from data
  cross apply dbo.DelimitedSplit8K(data.keyword,' ') as s
)

select
    strings.id
from strings
where len(strings.item) > 0  -- remove zero-length string and thus doubled-up delimters
group by strings.id
having count(itemnumber) <=3;

根据需要产生：

id
-----------
2
3
4
6
7

请注意，id = 7中的倍增空格会被删除零长度字符串进行压缩。

如何在SQL中查找包含少于三个单词的值？

2 个答案: