TO_NUMBER函数是Oracle SQL中用于将字符型数据转换为数字型数据的函数。下面是TO_NUMBER函数的一些灵活运用技巧：
SELECT TO_NUMBER('12345') FROM dual;
SELECT TO_NUMBER('1,234.56', '999G999D99') FROM dual;
SELECT TO_NUMBER('$1,234.56', 'L999G999D99') FROM dual;
SELECT TO_NUMBER(NULLIF('12345', ''), '99999') FROM dual;
SELECT TO_NUMBER('1.23456E+4', '9.99999EEEE') FROM dual;
SELECT TO_NUMBER('123.456', '999.999') FROM dual;
SELECT CASE WHEN TO_NUMBER('12345') > 10000 THEN '大于10000' ELSE '小于等于10000' END FROM dual;
这些技巧可以帮助你更灵活地使用TO_NUMBER函数在Oracle SQL中进行数据类型转换。
