Oracle数据类型转换

将日期型转换为字符串TO_CHAR()

SELECT
TO_CHAR (SYSDATE, 'YYYY-MM-DD HH24:MI:SS AM')
FROM DUAL

将数字型转换为字符串TO_CHAR()

SELECT
TO_CHAR(789.12333,'$99999.999') 
FROM DUAL;

将字符换转换为日期TO_DATE()

SELECT
TO_DATE ('20191024', 'YYYY-MM-DD')
FROM DUAL;

将字符串转换为数字TO_NUMBER()

SELECT
TO_NUMBER('110') 
FROM DUAL;