现在用的库里有一个MV是统计按小时的访问量的,数据如下代码:
SQL> select * from mv_time_stat;
TIME CNT
---------- ----------
0 187
1 51
2 34
3 19
4 19
5 20
6 50
7 107
8 682
9 1342
10 1854
11 1292
12 1416
13 1180
14 1217
15 1573
16 1785
17 1469
18 1892
19 1907
20 1602
21 1540
22 1013
23 441
24 rows selected.
某年月日,突发奇想,打算在sqlplus下面按上面的数据画个直方图出来,首先写了个竖列的(因为好写):
代码:
SQL> COL Time FORMAT A7
SQL> SELECT LPAD(DECODE(TIME,TO_CHAR(SYSDATE,'HH24'),'NOW: '
TO_CHAR(TIME),TO_CHAR(TIME)),7,' ') AS "Time",
2 SUBSTR(''LPAD('> 'CNT,CEIL(CNT/A.TOTAL*300)+
LENGTH(TO_CHAR(CNT))+1,'-'),1,35) AS " Count per hour"
3 FROM MV_TIME_STAT,(SELECT SUM(CNT) AS TOTAL FROM MV_TIME_STAT) A;
COL Time CLEAR
Time Count per hour
------- -----------------------------------------------------------------
0 --> 187
1 > 51
2 > 34
3 > 19
4 > 19
5 > 20
6 > 50
7 -> 107
NOW: 8 ---------> 682
9 -----------------> 1342
10 ------------------------> 1854
11 -----------------> 1292
12 ------------------> 1416
13 ---------------> 1180
14 ----------------> 1217
15 --------------------> 1573
16 -----------------------> 1785
17 -------------------> 1469
18 -------------------------> 1892
19 -------------------------> 1907
20 ---------------------> 1602
21 --------------------> 1540
22 -------------> 1013
23 -----> 441
24 rows selected.
然后又想,怎么样把它横过来,到网上查资料,又突击学习了下分析函数,写了一个过程是这个样子的:
代码:
CREATE OR REPLACE PROCEDURE HISTOGRAPH(HEIGHT NUMBER DEFAULT 15) AS
MAX_ONE NUMBER;
STR_LINE VARCHAR(120);
STR_TEMP VARCHAR(120);
I NUMBER;
BEGIN
DBMS_OUTPUT.PUT_LINE(LPAD('^',14,' '));
SELECT MAX(CNT) INTO MAX_ONE FROM MV_TIME_STAT;
FOR I IN 1 .. HEIGHT+1 LOOP
STR_LINE:=LPAD(TO_CHAR(MAX_ONE-(I-1)*MAX_ONE/HEIGHT,'99999')'-'
TO_CHAR(MAX_ONE-(I-2)*MAX_ONE/HEIGHT,'99999')'',14,'0');
SELECT MAX(SYS_CONNECT_BY_PATH(
DECODE(SIGN(CNT-MAX_ONE+(I-1)*MAX_ONE/HEIGHT),-1,
DECODE(SIGN(CNT-MAX_ONE+(I-2)*MAX_ONE/HEIGHT),-1,'^','*'),
''),
' ')) INTO STR_TEMP
FROM MV_TIME_STAT
START WITH TIME=0
CONNECT BY PRIOR TIME=TIME-1;
STR_LINE:=STR_LINESTR_TEMP;
DBMS_OUTPUT.PUT_LINE(REPLACE (STR_LINE,'^',' '));
END LOOP;
SELECT MAX(SYS_CONNECT_BY_PATH(TO_CHAR(TIME,'00'),'^')) INTO STR_TEMP
FROM MV_TIME_STAT
START WITH TIME=0
CONNECT BY PRIOR TIME=TIME-1;
DBMS_OUTPUT.PUT_LINE(LPAD('0',14,' ')LPAD('>',LENGTH(REPLACE(STR_TEMP,' '))+3,'-'));
DBMS_OUTPUT.PUT_LINE(REPLACE(LPAD('^',14,' ')REPLACE(STR_TEMP,' '),'^',' '));
END;
/
Procedure created.
SQL> exec histograph;
^
1907- 2034
1780- 1907
1653- 1780
1526- 1653
1398- 1526
1271- 1398
1144- 1271
1017- 1144
890- 1017
763- 890
636- 763
509- 636
381- 509
254- 381
127- 254
0- 127
0-------------------------------------------------------------------------->
00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23
PL/SQL procedure sUCcessfully completed.