最近有看到網上關於排序查詢的實現有兩個自己不常用的查詢語法，關於分析函式的用法，記之，鑑之，勉之；
在乙個表裡怎麼查詢每列資料的最大值和次大值？
withtt
as (select
case
when col1 in (1, 2) then empno else
null
endempno,
case
when col2 in (1, 2) then ename else
null
endename,
case
when col3 in (1, 2) then job else
null
endjob,
case
when col4 in (1, 2) then mgr else
null
endmgr,
case
when col5 in (1, 2) then hiredate else
null
endhiredate,
case
when col6 in (1, 2) then sal else
null
endsal,
case
when col7 in (1, 2) then comm else
null
endcomm,
case
when col8 in (1, 2) then deptno else
null
enddeptno
from (select
empno,
row_number ()
over (order
by empno desc
) col1,
ename,
row_number ()
over (order
by ename desc
) col2,
job,
row_number ()
over (order
by job desc
) col3,
mgr,
row_number ()
over (order
by mgr desc
) col4,
hiredate,
row_number ()
over (order
by hiredate desc
) col5,
sal,
row_number ()
over (order
by sal desc
) col6,
comm,
row_number ()
over (order
by comm desc
) col7,
deptno,
row_number ()
over (order
by deptno desc
) col8
from
emp))
select
max(empno) empno,
max(ename) ename,
max(job) job,
max(mgr) mgr,
max(hiredate) hiredate,
max(sal) sal,
max(comm) comm,
max(deptno) deptno
from
ttunion
allselect
min(empno) empno,
min(ename) ename,
min(job) job,
min(mgr) mgr,
min(hiredate) hiredate,
min(sal) sal,
min(comm) comm,
min(deptno) deptno
from tt
對一張表中的資料做如下操作啊，先對資料進行分分組，再在組內進行排序，再顯示每組中的前兩行
select*from (select
d.empno,
d.deptno,
sum(sal),
rank()
over(partition by deptno order
bysum(sal) desc
) rank
from
scott.emp d
group
by d.empno, d.deptno) where rank<
3
oracle之PLSQL小習題
求n的階乘 declare n number n s number 1 i number 1 sums number 0 begin for i in 1.n loop s s i sums sums s end loop dbms output.put line n 的階乘為 s dbms out...
Oracle 之PLSQL的常見命令
1.sql structured query language sql有許多關鍵字，以下語句是常用於開頭的語句 alter insert audit lock commit noaudit comment rename create revoke delete select drop update ...
Oracle基礎之PL SQL程式塊
pl sql塊由三個部分組成 說明部分 執行部分和異常處理部分。一段完整的pl sql程式塊結構如下所示 declare 說明部分 begin 塊開始標記 執行部分 exception 異常處理部分 end 塊結束標記 說明 1 說明部分 說明部分是可選的。由關鍵字declare引出，用於定義常量 ...