正如 Blogbeard 所说,您提供的查询不适用于 SQL Server。这是计算最常用单词的一种方法。这是基于一个函数,定界分割N4K,由 Jeff Moden 编写并由 SQL Server Central 社区成员改进。
ONLINE DEMO
WITH E1(N) AS (
SELECT 1 FROM (VALUES
(1),(1),(1),(1),(1),(1),(1),(1),(1),(1)
) t(N)
),
E2(N) AS (SELECT 1 FROM E1 a CROSS JOIN E1 b),
E4(N) AS (SELECT 1 FROM E2 a CROSS JOIN E2 b)
SELECT TOP 50
x.Item,
COUNT(*)
FROM Posts p
CROSS APPLY (
SELECT
ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
Item = LTRIM(RTRIM(SUBSTRING(p.Title, l.N1, l.L1)))
FROM (
SELECT s.N1,
L1 = ISNULL(NULLIF(CHARINDEX(' ',p.Title,s.N1),0)-s.N1,4000)
FROM(
SELECT 1 UNION ALL
SELECT t.N+1
FROM(
SELECT TOP (ISNULL(DATALENGTH(p.Title)/2,0))
ROW_NUMBER() OVER (ORDER BY (SELECT NULL))
FROM E4
) t(N)
WHERE SUBSTRING(p.Title ,t.N,1) = ' '
) s(N1)
) l(N1, L1)
) x
WHERE x.item <> ''
GROUP BY x.Item
ORDER BY COUNT(*) DESC
由于不允许创建函数,所以我就这样编写了。如果您有兴趣,这里是函数定义:
CREATE FUNCTION [dbo].[DelimitedSplitN4K](
@pString NVARCHAR(4000),
@pDelimiter NCHAR(1)
)
RETURNS TABLE WITH SCHEMABINDING AS
RETURN
WITH E1(N) AS (
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL
SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1 UNION ALL SELECT 1
),
E2(N) AS (SELECT 1 FROM E1 a, E1 b),
E4(N) AS (SELECT 1 FROM E2 a, E2 b),
cteTally(N) AS(
SELECT TOP (ISNULL(DATALENGTH(@pString)/2,0)) ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM E4
),
cteStart(N1) AS (
SELECT 1 UNION ALL
SELECT t.N+1 FROM cteTally t WHERE SUBSTRING(@pString,t.N,1) = @pDelimiter
),
cteLen(N1,L1) AS(
SELECT s.N1,
ISNULL(NULLIF(CHARINDEX(@pDelimiter,@pString,s.N1),0)-s.N1,4000)
FROM cteStart s
)
SELECT
ItemNumber = ROW_NUMBER() OVER(ORDER BY l.N1),
Item = SUBSTRING(@pString, l.N1, l.L1)
FROM cteLen l
;
以下是您将如何使用它:
SELECT TOP 50
x.Item,
COUNT(*)
FROM Posts p
CROSS APPLY dbo.DelimitedSplitN4K(p.Title, ' ') x
WHERE LTRIM(RTRIM(x.Item)) <> ''
GROUP BY x.Item
ORDER BY COUNT(*) DESC
结果:
Item
-------- -------
to 3812411
in 3331522
a 2543636
How 1770915
the 1534298
with 1341632
of 1297468
and 1166664
on 970554
from 964449
for 886007
not 835979
is 704724
using 703007
I 633838
- 632441
an 548450
when 449169
file 409717
how 358745
data 335271
do 323854
can 310298
get 305922
or 266317
error 263563
use 258408
value 254392
it 251254
my 238902
function 235832
by 231025
Android 228308
as 216654
array 209157
working 207445
does 207274
Is 205613
multiple 203336
that 197826
Why 196979
into 196591
after 192056
string 189053
PHP 187018
one 182360
class 179965
if 179590
text 174878
table 169393