Ecco un esempio autonomo, con dati di test facilmente manipolabili.
Con questo esempio, se hai un nome con più di tre parti, tutte le cose "extra" verranno inserite nel campo LAST_NAME. Viene fatta un'eccezione per stringhe specifiche identificate come "titoli", come "DR", "MRS" e "MR".
Se manca il secondo nome, ottieni solo FIRST_NAME e LAST_NAME (MIDDLE_NAME sarà NULL).
Potresti distruggerlo in un gigantesco blob annidato di SUBSTRING, ma la leggibilità è già abbastanza difficile come lo è quando lo fai in SQL.
Modifica:gestisci i seguenti casi speciali:
1 - Il campo NOME è NULL
2 - Il campo NAME contiene spazi iniziali/finali
3 - Il campo NAME ha> 1 spazio consecutivo all'interno del nome
4 - Il campo NOME contiene SOLO il nome
5 - Includi il nome completo originale nell'output finale come una colonna separata, per maggiore leggibilità
6 - Gestisci un elenco specifico di prefissi come una colonna "titolo" separata
SELECT
FIRST_NAME.ORIGINAL_INPUT_DATA
,FIRST_NAME.TITLE
,FIRST_NAME.FIRST_NAME
,CASE WHEN 0 = CHARINDEX(' ',FIRST_NAME.REST_OF_NAME)
THEN NULL --no more spaces? assume rest is the last name
ELSE SUBSTRING(
FIRST_NAME.REST_OF_NAME
,1
,CHARINDEX(' ',FIRST_NAME.REST_OF_NAME)-1
)
END AS MIDDLE_NAME
,SUBSTRING(
FIRST_NAME.REST_OF_NAME
,1 + CHARINDEX(' ',FIRST_NAME.REST_OF_NAME)
,LEN(FIRST_NAME.REST_OF_NAME)
) AS LAST_NAME
FROM
(
SELECT
TITLE.TITLE
,CASE WHEN 0 = CHARINDEX(' ',TITLE.REST_OF_NAME)
THEN TITLE.REST_OF_NAME --No space? return the whole thing
ELSE SUBSTRING(
TITLE.REST_OF_NAME
,1
,CHARINDEX(' ',TITLE.REST_OF_NAME)-1
)
END AS FIRST_NAME
,CASE WHEN 0 = CHARINDEX(' ',TITLE.REST_OF_NAME)
THEN NULL --no spaces @ all? then 1st name is all we have
ELSE SUBSTRING(
TITLE.REST_OF_NAME
,CHARINDEX(' ',TITLE.REST_OF_NAME)+1
,LEN(TITLE.REST_OF_NAME)
)
END AS REST_OF_NAME
,TITLE.ORIGINAL_INPUT_DATA
FROM
(
SELECT
--if the first three characters are in this list,
--then pull it as a "title". otherwise return NULL for title.
CASE WHEN SUBSTRING(TEST_DATA.FULL_NAME,1,3) IN ('MR ','MS ','DR ','MRS')
THEN LTRIM(RTRIM(SUBSTRING(TEST_DATA.FULL_NAME,1,3)))
ELSE NULL
END AS TITLE
--if you change the list, don't forget to change it here, too.
--so much for the DRY prinicple...
,CASE WHEN SUBSTRING(TEST_DATA.FULL_NAME,1,3) IN ('MR ','MS ','DR ','MRS')
THEN LTRIM(RTRIM(SUBSTRING(TEST_DATA.FULL_NAME,4,LEN(TEST_DATA.FULL_NAME))))
ELSE LTRIM(RTRIM(TEST_DATA.FULL_NAME))
END AS REST_OF_NAME
,TEST_DATA.ORIGINAL_INPUT_DATA
FROM
(
SELECT
--trim leading & trailing spaces before trying to process
--disallow extra spaces *within* the name
REPLACE(REPLACE(LTRIM(RTRIM(FULL_NAME)),' ',' '),' ',' ') AS FULL_NAME
,FULL_NAME AS ORIGINAL_INPUT_DATA
FROM
(
--if you use this, then replace the following
--block with your actual table
SELECT 'GEORGE W BUSH' AS FULL_NAME
UNION SELECT 'SUSAN B ANTHONY' AS FULL_NAME
UNION SELECT 'ALEXANDER HAMILTON' AS FULL_NAME
UNION SELECT 'OSAMA BIN LADEN JR' AS FULL_NAME
UNION SELECT 'MARTIN J VAN BUREN SENIOR III' AS FULL_NAME
UNION SELECT 'TOMMY' AS FULL_NAME
UNION SELECT 'BILLY' AS FULL_NAME
UNION SELECT NULL AS FULL_NAME
UNION SELECT ' ' AS FULL_NAME
UNION SELECT ' JOHN JACOB SMITH' AS FULL_NAME
UNION SELECT ' DR SANJAY GUPTA' AS FULL_NAME
UNION SELECT 'DR JOHN S HOPKINS' AS FULL_NAME
UNION SELECT ' MRS SUSAN ADAMS' AS FULL_NAME
UNION SELECT ' MS AUGUSTA ADA KING ' AS FULL_NAME
) RAW_DATA
) TEST_DATA
) TITLE
) FIRST_NAME
