Oracle 11g Release 2

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CREATE TABLE table_name ( col ) AS
SELECT 'United States of America' FROM DUAL UNION ALL
SELECT 'ABCDEFGHIJKLM' FROM DUAL UNION ALL
SELECT 'A B' || CHR(9) || 'C' || CHR(13) || CHR(10) || 'D E F G H I J K L M' FROM DUAL;
3 rows affected

select substr(replace(col, ' ', ''), 1, 8)
FROM   table_name

SUBSTR(REPLACE(COL,'',''),1,8)

UnitedSt

ABCDEFGH

AB C
DE

SELECT SUBSTR(REGEXP_REPLACE(col, '\s+'), 1, 8)
FROM   table_name

SUBSTR(REGEXP_REPLACE(COL,'\S+'),1,8)

UnitedSt

ABCDEFGH

ABCDEFGH