沉迷数据无法自拔

DDL单行函数单行函数基础SELECT UPPER(‘abc’) from dual; -->ABCSELECT lower(‘EFG’) from dual; -->efgSELECT TRUNC(123.456) FROM DUAL ; -->123 直接截取SELECT TRUNC(123.456,2) FROM DUAL ; -->123.45SELECT ROUND(456.789) FROM DUAL; -->457 四舍五入SELECT RO