Примеры
substring-before('12-May-1998', '-')
-> '12'
substring-before('12 May 1998', ' ')
-> '12'
substring-before('12 May 1998', ' ')
-> '12'
substring-before('12 May 1998', '-')
-> ''
Примеры
substring-before('12-May-1998', '-')
-> '12'
substring-before('12 May 1998', ' ')
-> '12'
substring-before('12 May 1998', ' ')
-> '12'
substring-before('12 May 1998', '-')
-> ''