oracle计算某个字段或字符中指定模式的数量

select length('a=b,c=d,e=f') - lengthb(replace('a=b,c=d,e=f', '=', ''))
  from dual;

SELECT REGEXP_COUNT('a=b,c=d,e=f', '=', 1, 'i') Result from dual;

SELECT REGEXP_COUNT('123123123123', '123', 3, 'i') COUNT from dual;