=rand() 的 T-SQL 等价物

Posted 2023-02-25

【中文标题】=rand() 的 T-SQL 等价物

【英文标题】：T-SQL equivalent of =rand()

【发布时间】：2010-11-10 17:38:25

【问题描述】：

我有几个内容表，我想用随机的文本段落填充它们。在 MS Word 中，我可以简单地输入 =rand() 和 presto！我得到了三段新鲜的文本。

是否有可以使用 t-sql 生成随机字典单词的 SQL 脚本/命令？

【问题讨论】：

这是一个巧妙的技巧。 word 中是否有其他可用的 =func() 列表？

这里有更多关于 rand()/lorem() 的信息，供好奇的人（就像我一样）support.microsoft.com/kb/212251

【参考方案1】：

;
declare 
    @Lorem nvarchar(max),
    @RowsToGen int,
    @Factor int

select
    @Lorem = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.',
    @RowsToGen = 200

-- strip punctuations
set @Lorem = replace(@Lorem, ',', '')
set @Lorem = replace(@Lorem, '.', '')

;
with
Num1(Pos) as
(
    select cast(1 as int)
    union all 
    select cast(Pos + 1 as int) from Num1 where Pos < len(@Lorem)
),
Words as
(
    select substring(@Lorem, Pos, charindex(' ', @Lorem + ' ', Pos) - Pos) as Word
        from Num1 where Pos <= len(@Lorem) and substring(',' + @Lorem, Pos, 1) = ' '
),
WordsCnt(Factor) as
(
    select @RowsToGen / count(*) + 1 from Words
),
Num2(Pos) as
(
    select cast(1 as int)
    union all 
    select cast(Pos + 1 as int) from Num2 cross join WordsCnt where Pos < WordsCnt. Factor
)
select top (@RowsToGen) 
    Word 
from 
    Num2 
cross join 
    Words
order by newid()
option (maxrecursion 0)     

【讨论】：

我喜欢这个。我如何将其旋转为每行 20 个单词而不是每行一个单词？

@Raj More，抱歉不在了，请在底部找到“句子”版本。

【参考方案2】：

根据 Raj More 的要求，这是另一个版本，它给出一个句子而不是每行一个单词。

;
declare 
    @Lorem nvarchar(max),
    @SentenceToGen int,
    @WordsPerSentence int,
    @Factor int

select
    @Lorem = 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.',
    @SentenceToGen = 200,
    @WordsPerSentence = 10

-- strip punctuations
set @Lorem = replace(@Lorem, ',', '')
set @Lorem = replace(@Lorem, '.', '')

;
with
Num1(Pos) as -- number of chars in @Lorem
(
    select cast(1 as int)
    union all 
    select cast(Pos + 1 as int) from Num1 where Pos < len(@Lorem)
),
Words as
(
    select lower(substring(@Lorem, Pos, charindex(' ', @Lorem + ' ', Pos) - Pos)) as Word
        from Num1 where Pos <= len(@Lorem) and substring(',' + @Lorem, Pos, 1) = ' '
),
WordsCnt(Factor) as
(
    select ceiling(cast(@SentenceToGen * @WordsPerSentence as float) / count(*)) from Words
),
Num2(Pos) as -- product of words required, to be divided by number of words found in @Lorem
(
    select cast(1 as int)
    union all 
    select cast(Pos + 1 as int) from Num2 cross join WordsCnt where Pos < WordsCnt.Factor
),
Sentences as
(
    select
        ntile(@SentenceToGen) over (order by newid()) as SentenceId,
        Word
    from 
        Num2 
    cross join 
        Words
),
Num3(Pos) as -- list of SentenceId
(
    select distinct SentenceId from Sentences
)
select 
    (
        select top (@WordsPerSentence) 
            Word + ' ' 
        from 
            Sentences 
        where 
            Sentences.SentenceId = Num3.Pos 
        for xml path('')
    ) 
    as Sentence
from
    Num3    
option (maxrecursion 0)         

【参考方案3】：

没有内置任何东西，但很容易做到：

create table DictionaryWords 
(
    Id int primary key identity (1,1),
    Word nvarchar(100) not null
)
go

insert DictionaryWords values ('the')
insert DictionaryWords values ('quick')
insert DictionaryWords values ('brown')
insert DictionaryWords values ('fox')
insert DictionaryWords values ('jumped')
insert DictionaryWords values ('over')
insert DictionaryWords values ('the')
insert DictionaryWords values ('lazy')
insert DictionaryWords values ('dog')
go

create procedure dbo.CreateRandomText(@numWords int, @text nvarchar(max) out)
as
begin

    declare @rowcount int
    select @rowcount = count(*) from DictionaryWords

    select @text = ''

    while @numWords <> 0
        select @text = @text + ' ' + Word, @numWords = @numWords - 1
        from DictionaryWords
        where Id = cast(@rowcount * rand() as integer)

end
go

declare @text nvarchar(max)
exec CreateRandomText 10, @text out
select @text