应用场景254 ：字符型函数
SET ServerOutput ON;
BEGIN
dbms_output.put_line(ASCII('ABC'));
END;
/
COL DEP_NAME FORMAT A20
SELECT Dep_name, LENGTH(Dep_name) FROM HRMAN.Departments;
SET ServerOutput ON;
BEGIN
dbms_output.put_line(UPPER('abc'));
END;
/
应用场景255 ：日期型函数
sysdate函数：
SET ServerOutput ON;
BEGIN
dbms_output.put_line(SYSDATE);
END;
/
TO_CHAR函数
SET ServerOutput ON;
BEGIN
dbms_output.put_line(TO_CHAR(SYSDATE));
END;
/
last_day函数
SET ServerOutput ON;
BEGIN
dbms_output.put_line(LAST_DAY(SYSDATE));
END;
/
TO_DATE函数
SET ServerOutput ON;
BEGIN
dbms_output.put_line(TO_DATE('2010-2-5', 'yyyy-mm-dd'));
END;
/
months_between函数：
SET ServerOutput ON;
DECLARE
date1 VARCHAR2(20) := '2010-06-05';
date2 VARCHAR2(20) := '2010-10-05';
BEGIN
dbms_output.put_line(MONTHS_BETWEEN(TO_DATE(date2,'yyyy-mm-dd'), TO_DATE(date1, 'yyyy-mm-
dd')));
END;
/
round函数：
SET ServerOutput ON;
BEGIN
dbms_output.put_line(TO_CHAR(ROUND (SYSDATE, 'MM')));
END;
应用场景256 ：统计函数
count函数
SELECT COUNT(Dep_id) FROM HRMAN.Departments;
MAX函数
SELECT MAX(Dep_id) FROM HRMAN.Departments;
MIN函数
SELECT MIN(Dep_id) FROM HRMAN.Departments;
?