Oracle PL/SQL 打印字符串的每个字母
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Oracle PL / SQL printing each letter of a string
提问by Computerphile
I need to print out the letters of the word 'Hello' each on it's own , I wrote this :
我需要单独打印出“你好”这个词的字母，我是这样写的：
Declare
c1 Number:=1;
c2 Varchar2(5);
begin
for c1 in 1..5
loop
select substr('Hello' , c1 , 1 ) into c2 from dual;
dbms_output.put_line(c2);
end loop;
end;
but it skips the first two letter and the out is
但它跳过前两个字母，输出是
l
l
o
any ideas what might be the problem? Thank you.
任何想法可能是什么问题？谢谢你。
回答by mahi_0707
Better to have Loop end limit For i in 1..v_lengthThis way you do not have to change the Looplimit each time you run.
最好有循环结束限制 For i in 1..v_length这样你就不必在Loop每次运行时更改限制。
Create or replace procedure print_string( IN_string IN varchar2 )
AS
v_length number(10);
v_out varchar2(20);
Begin
v_length := length(IN_string);
for i in 1..v_length
Loop
v_out := substr(IN_string,i,1) ;
DBMS_OUTPUT.PUT_LINE(v_out);
End loop;
DBMS_OUTPUT.PUT_LINE('Text printed: ' || IN_string);
End;
-- Procedure created.
BEGIN
print_string('Hello');
END;
-- Output:
H
e
l
l
o
Text printed: Hello
Statement processed.
回答by Gary_W
It can be done in a single select too:
它也可以在单个选择中完成：
SQL> select substr('hello', level, 1) Letter
2 from dual
3 connect by level <= length('hello');
L
-
h
e
l
l
o
SQL>
回答by Nancy Guruswamy
The script you have written is right.
你写的剧本是对的。
Declare
c1 Number:=1;
c2 Varchar2(5);
begin
for c1 in 1..5
loop
select substr('Hello' , c1 , 1 ) into c2 from dual;
dbms_output.put_line(c2);
end LOOP;
end;
output:-
输出：-
H
e
l
l
o
回答by Nick Pierpoint
Your script:
你的脚本：
declare
c1 number := 1;
c2 varchar2(5);
begin
for c1 in 1 .. 5 loop
select substr('Hello', c1, 1) into c2 from dual;
dbms_output.put_line(c2);
end loop;
end;
Outputs the following:
输出以下内容：
H
e
l
l
o
All looks fine for me.
对我来说一切都很好。
What output do you get?
你得到什么输出？
