在sqlplus中使用emacs编辑sql
$ORACLE_HOME/sqlplus/admin:
login.sql
define _editor='emacs -nw' //在terminal中edit
// define _editor=vim
set serveroutput on size 1000000
set trimspool on
set long 5000
set linesize 100
set pagesize 9999
column plan_plus_exp format a80
column global_name new_value gname
set termout off
select lower(user) || '@' ||
decode(global_name, 'ORCL.REGRESS.RDBMS.DEV.US.ORACLE.COM', 'ORCL.10G',
global_name) global_name
from global_name;
set sqlprompt '&gname>'
set termout on
In Oracle/PLSQL, the decode function has the functionality of an IF-THEN-ELSE statement.
The syntax for the decode function is:
decode( expression , search , result [, search , result]... [, default] )
For example:
You could use the decode function in an SQL statement as follows:
SELECT supplier_name,
decode(supplier_id,
10000, 'IBM',
10001, 'Microsoft',
10002, 'Hewlett Packard',
'Gateway') result
FROM suppliers;
The above decode statement is equivalent to the following IF-THEN-ELSE statement:
IF supplier_id = 10000
THEN
result := 'IBM';
ELSIF supplier_id = 10001
THEN
result := 'Microsoft';
ELSIF supplier_id = 10002
THEN
result := 'Hewlett Packard';
ELSE
result := 'Gateway';
END IF;
The decode function will compare each supplier_id value, one by one.
select * from
(select a.*, rownum rn
from (select * from all_users) a
)
where rn between 25 and 27
select * from
(select a.*, rownum rn from all_users a where rownum <=27)
where rn >=25;