t-sql:计算 varchar 列中单词的出现次数
我想使用 ContainsTable 获取嵌入在名为 description 的 t-sql nvarchar 列中的单个单词的计数.如果我提供红色"或绿色"的标准,我怎么知道哪个真正匹配?简而言之,我正在尝试进行字数统计,并且正在寻找最佳方法.
I want to use ContainsTable to get counts on individual words embedded in a t-sql nvarchar column called description. If I provide the criteria of Red Or Green, how can I tell which one actually matched off? In short, i am trying to do word counts and am looking for the best approach.
提前致谢
推荐答案
给你:
drop function dbo.CountOccurrencesOfWord
go
create function dbo.CountOccurrencesOfWord(
@text varchar(max),
@word varchar(8000)
)
returns int
as
begin
declare
@index int = charindex(@word, @text, 1),
@len int = len(@word),
@count int = 0
while @index > 0 begin
set @count = @count + 1
set @index = charindex(@word, @text, @index + @len)
end
return @count
end
GO
if object_id('tempdb..#example') is not null
drop table #example
create table #example(
description nvarchar(4000) not null
)
insert into #example select 'red yellow green red white blue red redred red green red'
insert into #example select 'red yellow green red'
insert into #example select 'orange grey green'
insert into #example select ''
insert into #example select 'magenta aqua cyan'
select dbo.CountOccurrencesOfWord(description, 'red'), description
from #example
注意事项 - 这种逻辑在 t-sql 中可能非常昂贵.
word of caution- this kind of logic can be quite costly in t-sql.
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