The SUBSTRING_INDEX function counts the separators included in the partial character string and will return the partial character string before countth. The return value is a VARCHAR type.
SUBSTRING_INDEX (string, delim, count)
SELECT SUBSTRING_INDEX('www.cubrid.org','.','2');
substring_index('www.cubrid.org', '.', '2')
======================
'www.cubrid'
SELECT SUBSTRING_INDEX('www.cubrid.org','.','2.3');
substring_index('www.cubrid.org', '.', '2.3')
======================
'www.cubrid'
SELECT SUBSTRING_INDEX('www.cubrid.org',':','2.3');
substring_index('www.cubrid.org', ':', '2.3')
======================
'www.cubrid.org'
SELECT SUBSTRING_INDEX('www.cubrid.org','cubrid',1);
substring_index('www.cubrid.org', 'cubrid', 1)
======================
'www.'
SELECT SUBSTRING_INDEX('www.cubrid.org','.',100);
substring_index('www.cubrid.org', '.', 100)
======================
'www.cubrid.org'