问题
Want to search the string using PATINDEX and SOUNDEX.
I have the following table with some sample data to search the given string using PATINDEX and SOUNDEX.
create table tbl_pat_soundex
(
col_str varchar(max)
);
insert into tbl_pat_soundex values('Smith A Steve');
insert into tbl_pat_soundex values('Steve A Smyth');
insert into tbl_pat_soundex values('A Smeeth Stive');
insert into tbl_pat_soundex values('Steve Smith A');
insert into tbl_pat_soundex values('Smit Steve A');
String to search:- 'Smith A Steve'
SELECT col_str,PATINDEX('%Smith%',col_str) [Smith],PATINDEX('%A%',col_str) [A],PATINDEX('%Steve%',col_str) [Steve]
FROM tbl_pat_soundex
Getting Output:
col_str Smith A Steve
---------------------------------
Smith A Steve 1 7 9
Steve A Smyth 0 7 1
A Smeeth Stive 0 1 0
Steve Smith A 7 13 1
Smit Steve A 0 12 6
Expected Output:
col_str Smith A Steve
---------------------------------
Smith A Steve 1 7 9
Steve A Smyth 9 7 1
A Smeeth Stive 3 1 10
Steve Smith A 7 13 1
Smit Steve A 1 12 6
Tried:
SELECT col_str,
PATINDEX('%'+soundex('Smith')+'%',soundex(col_str)) [Smith],
PATINDEX('%'+soundex('A')+'%',soundex(col_str)) [A],
PATINDEX('%'+soundex('Steve')+'%',soundex(col_str)) [Steve]
FROM tbl_pat_soundex
But getting unexpected result:
col_str Smith A Steve
---------------------------------
Smith A Steve 1 0 0
Steve A Smyth 0 0 1
A Smeeth Stive 0 1 0
Steve Smith A 0 0 1
Smit Steve A 1 0 0
Note: I have 100 Millions of records in the table to search for.
回答1:
Here's one option, not sure how it would perform with 100 million records considering all that you need to do. You'll have to test that out.
At a high level how I understand this is you basically need
- Search all words in a string based on the words of another string
- Returning the character starting position in the original string where that word equals or sounds like the search word.
You can use DIFFERENCE() for the comparison:
DIFFERENCE compares two different SOUNDEX values, and returns an integer value. This value measures the degree that the SOUNDEX values match, on a scale of 0 to 4. A value of 0 indicates weak or no similarity between the SOUNDEX values; 4 indicates strongly similar, or even identically matching, SOUNDEX values.
You'll need to split the string based on the space ' ' and since you're 2008 you'd have to roll your own function.
I used the XML function from here, https://sqlperformance.com/2012/07/t-sql-queries/split-strings, for my examples, you'll obviously need to adjust if you have your own or want to use something different:
CREATE FUNCTION dbo.SplitStrings_XML
(
@List NVARCHAR(MAX),
@Delimiter NVARCHAR(255)
)
RETURNS TABLE
WITH SCHEMABINDING
AS
RETURN
(
SELECT Item = y.i.value('(./text())[1]', 'nvarchar(4000)')
FROM
(
SELECT x = CONVERT(XML, '<i>'
+ REPLACE(@List, @Delimiter, '</i><i>')
+ '</i>').query('.')
) AS a CROSS APPLY x.nodes('i') AS y(i)
);
GO
I switched and use table variables to show the example, I would suggest not doing that with the amount of data you have and create and use physical tables.
Option 1 - Not dynamic:
DECLARE @tbl_pat_soundex TABLE
(
[col_str] VARCHAR(MAX)
);
INSERT INTO @tbl_pat_soundex
VALUES ( 'Smith A Steve' )
,( 'Steve A Smyth' )
,( 'A Smeeth Stive' )
,( 'Steve Smith A' )
,( 'Smit Steve A' )
SELECT DISTINCT [aa].[col_str]
, MAX([aa].[Smith]) OVER ( PARTITION BY [aa].[col_str] ) AS [Smith]
, MAX([aa].[A]) OVER ( PARTITION BY [aa].[col_str] ) AS [A]
, MAX([aa].[Steve]) OVER ( PARTITION BY [aa].[col_str] ) AS [Steve]
FROM (
SELECT [a].[col_str]
, CASE WHEN DIFFERENCE([b].[item], 'Smith') = 4 THEN
CHARINDEX([b].[item], [a].[col_str])
ELSE 0
END AS [Smith]
, CASE WHEN DIFFERENCE([b].[item], 'A') = 4 THEN
CHARINDEX([b].[item], [a].[col_str])
ELSE 0
END AS [A]
, CASE WHEN DIFFERENCE([b].[item], 'Steve') = 4 THEN
CHARINDEX([b].[item], [a].[col_str])
ELSE 0
END AS [Steve]
FROM @tbl_pat_soundex [a]
CROSS APPLY [dbo].[SplitStrings_XML]([a].[col_str], ' ') [b]
) AS [aa];
- Using the function we split the string into individual words
- Then we use a case statement to check the DIFFERENCE value
- If that DIFFERENCE value equals 4 we then return the CHARINDEX value of the original word against string.
- If doesn't equal we return 0
Then from there it's a matter of getting the max value of each based on the original string:
, MAX([aa].[Smith]) OVER ( PARTITION BY [aa].[col_str] ) AS [Smith]
, MAX([aa].[A]) OVER ( PARTITION BY [aa].[col_str] ) AS [A]
, MAX([aa].[Steve]) OVER ( PARTITION BY [aa].[col_str] ) AS [Steve]
To get you your final results:
Option 2 - Dynamic with a pivot:
We'll declare the string we want to search, split that out and search for those individuals words in the original string and then pivot the results.
--This example is using global temp tables as it's showing how
--to build a dynamic pivot
IF OBJECT_ID('tempdb..##tbl_pat_soundex') IS NOT NULL
DROP TABLE [##tbl_pat_soundex];
IF OBJECT_ID('tempdb..##tbl_col_str_SearchString') IS NOT NULL
DROP TABLE [##tbl_col_str_SearchString];
CREATE TABLE [##tbl_pat_soundex]
(
[col_str] VARCHAR(MAX)
);
INSERT INTO [##tbl_pat_soundex]
VALUES ( 'Smith A Steve' )
, ( 'Steve A Smyth' )
, ( 'A Smeeth Stive' )
, ( 'Steve Smith A' )
, ( 'Smit Steve A' );
--What are you searching for?
DECLARE @SearchString NVARCHAR(200);
SET @SearchString = N'Smith A Steve';
--We build a table we load with every combination of the words from the string and the words from the SearchString for easier comparison.
CREATE TABLE [##tbl_col_str_SearchString]
(
[col_str] NVARCHAR(MAX)
, [col_str_value] NVARCHAR(MAX)
, [SearchValue] NVARCHAR(200)
);
--Load that table for comparison
--split our original string into individual words
--also split our search string into individual words and give me all combinations.
INSERT INTO [##tbl_col_str_SearchString] (
[col_str]
, [col_str_value]
, [SearchValue]
)
SELECT DISTINCT [a].[col_str]
, [b].[item]
, [c].[item]
FROM [##tbl_pat_soundex] [a]
CROSS APPLY [dbo].[SplitStrings_XML]([a].[col_str], ' ') [b]
CROSS APPLY [dbo].[SplitStrings_XML](@SearchString, ' ') [c]
ORDER BY [a].[col_str];
--Then we can easily compare each word and search word for those that match or sound alike using DIFFERNCE()
SELECT [col_str], [col_str_value], [SearchValue], CASE WHEN DIFFERENCE([col_str_value], [SearchValue]) = 4 THEN CHARINDEX([col_str_value], [col_str]) ELSE 0 END AS [Match] FROM ##tbl_col_str_SearchString
--Then we can pivot on it
--and we will need to make it dynamic since we are not sure what what @SearchString could be.
DECLARE @PivotSQL NVARCHAR(MAX);
DECLARE @pivotColumn NVARCHAR(MAX);
SET @pivotColumn = N'[' + REPLACE(@SearchString, ' ', '],[') + N']';
SET @PivotSQL = N'SELECT * FROM (
SELECT [col_str], [SearchValue], CASE WHEN DIFFERENCE([col_str_value], [SearchValue]) = 4 THEN CHARINDEX([col_str_value], [col_str]) ELSE 0 END AS [Match] FROM ##tbl_col_str_SearchString
) aa
PIVOT (MAX([Match]) FOR [SearchValue] IN (' + @pivotColumn
+ N')) AS MaxMatch
ORDER BY [MaxMatch].[col_str]
';
--Giving us the final results.
EXEC sp_executesql @PivotSQL
来源：https://stackoverflow.com/questions/53519032/patindex-with-soundex