oracle单行函数之字符函数

 1 SQL> select lower(‘Hello WorLD‘),upper(‘Hello WorLD‘),initcap(‘Hello WorLD‘) from dual;
 2  
 3 LOWER(‘HELLOWORLD‘) UPPER(‘HELLOWORLD‘) INITCAP(‘HELLOWORLD‘)
 4 ------------------- ------------------- ---------------------
 5 hello world         HELLO WORLD         Hello World
 6  
 7 SQL> select concat(‘Hello‘,‘world‘) from dual;
 8  
 9 CONCAT(‘HELLO‘,‘WORLD‘)
10 -----------------------
11 Helloworld
12  
13 SQL> select substr(‘Hello world‘,4),substr(‘Hello world‘,4,4) from dual;
14  
15 SUBSTR(‘HELLOWORLD‘,4) SUBSTR(‘HELLOWORLD‘,4,4)
16 ---------------------- ------------------------
17 lo world               lo w
18 
19  
20 SQL> select length(‘Hello world‘),lengthb(‘Hello world‘),length(‘武汉‘),lengthb(‘武汉‘) from dual;
21  
22 LENGTH(‘HELLOWORLD‘) LENGTHB(‘HELLOWORLD‘)   LENGTH(‘武汉‘)   LENGTHB(‘武汉‘)
23 -------------------- --------------------- -------------- ---------------
24                   11                    11              2               6
25  
26 SQL> select instr(‘Hello world‘,‘w‘) from dual;
27  
28 INSTR(‘HELLOWORLD‘,‘W‘)
29 -----------------------
30                       7
31  
32 SQL> select lpad(‘Hello‘,10,‘*‘),rpad(‘Hello‘,10,‘*‘) from dual;
33  
34 LPAD(‘HELLO‘,10,‘*‘) RPAD(‘HELLO‘,10,‘*‘)
35 -------------------- --------------------
36 *****Hello           Hello*****
37  
38 SQL> select trim(‘H‘ from ‘Hello world HHHH‘) from dual;
39  
40 TRIM(‘H‘FROM‘HELLOWORLDHHHH‘)
41 -----------------------------
42 ello world
43  
44 SQL> select replace(‘Hello world‘,‘l‘,‘*‘) from dual;
45  
46 REPLACE(‘HELLOWORLD‘,‘L‘,‘*‘)
47 -----------------------------
48 He**o wor*d