Oracle總結（1）
阿新 • • 發佈：2019-01-25
一.基本查詢
1.基本命令
1> show user 當前使用者
2> select * from tab; 當前使用者下的表
tab: 資料字典(表)
3> desc 表名-----------查看錶結構
4> set linesize 120 --設定行寬
5> col ename for a8 --設定行寬
col sal for 9999
6> c命令
SQL> select *
2 form emp;
form emp
*
第 2 行出現錯誤:
ORA-00923: 未找到要求的 FROM 關鍵字
SQL> --c 命令
SQL> 2
2* form emp
SQL> c /form/from
2* from emp
SQL> /
7> --DISTINCT 去掉重複記錄
select DISTINCT deptno,job from emp;
--DISTINCT作用於後面所有的列
8> --連線符
concat('Hello',' World')
9> --dual:偽表
select 3+2 from dual;
3+2
----------
5
10> save c:\a.sql -----儲存位sql指令碼
已建立 file c:\a.sql
@c:\a.sql ---------執行sql指令碼
2.過濾和排序
1> --字元大小寫敏感
2> --日期格式敏感
select sysdate from dual
SYSDATE
--------------
19-6月 -13
-----------------預設格式-----------------
SQL> select *
2 from v$nls_parameters;
PARAMETER VALUE
------------------------------ ----------------------------------------------------------------
NLS_LANGUAGE SIMPLIFIED CHINESE
NLS_TERRITORY CHINA
NLS_CURRENCY ￥
NLS_ISO_CURRENCY CHINA
NLS_NUMERIC_CHARACTERS .,
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE SIMPLIFIED CHINESE
NLS_CHARACTERSET ZHS16GBK
NLS_SORT BINARY
NLS_TIME_FORMAT HH.MI.SSXFF AM
PARAMETER VALUE
------------------------------ ----------------------------------------------------------------
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY ￥
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS BYTE
NLS_NCHAR_CONV_EXCP FALSE
已選擇19行。
------------------------修改預設格式---------------------
SQL> alter session set NLS_DATE_FORMAT='yyyy-mm-dd';
會話已更改。
3> between and 在...之間 (小值在前 大值在後)
SQL> --查詢薪水1000~2000之間的員工
SQL> select *
2 from emp
3 where sal between 1000 and 2000;
4> in 在集合中 not in 不在集合中
SQL> --查詢部門號是10和20的員工
SQL> select *
2 from emp
3 where deptno in (10,20);
5> like 模糊查詢 %(任意多個) _(任意一個)
--查詢名字是4個字的員工
select *
from emp
where ename like '____';
-------------------------------------
--查詢名字中含有下劃線的員工
select *
from emp
where ename like '%\_%' escape '\';
6> 排序
SQL> select *
2 from emp
3 order by sal;
SQL> --a命令 append
SQL> a desc
3* order by sal desc
SQL> /
-------------------------------------------------
--order by後面+列名 表示式 別名 序號
select *
2 from emp
3 order by comm desc
4* nulls last -----空值最後
3.單行函式
1> --NULLIF(a,b) 當a=b時, 返回null，否則返回a
SQL> select nullif('abc','abcd') from dual;
NUL
---
abc
2> --COALESCE :從左往右找到第一個不為null的值
select comm,sal,COALESCE(comm,sal) from emp;
3> case...end
SQL> --條件表示式
SQL> --漲工資，總裁1000 經理800 其他400
SQL> select ename,job,sal 漲前薪水,
2 case job when 'PRESIDENT' then sal+1000
3 when 'MANAGER' then sal+800
4 else sal+400
5 end 漲後薪水
6 from emp;
4> SQL> select ename,job,sal 漲前薪水,
2 decode(job,'PRESIDENT',sal+1000,
3 'MANAGER',sal+800,
4 sal+400) 漲後薪水
5 from emp;
4.組函式
1> --工資總額
SQL> select sum(sal) from emp;
2> --人數
SQL> select count(*) from emp;
3> --平均工資
SQL> select sum(sal)/count(*) 一,avg(sal) 二 from emp;
4> --平均獎金
SQL> select sum(comm)/count(*) 一, sum(comm)/count(comm) 二, avg(comm) 三
2 from emp;
一 二 三
---------- ---------- ----------
157.142857 550 550
5> --分組資料
SQL> --求每個部門的平均工資
SQL> select deptno,avg(sal)
2 from emp
3 group by deptno;
DEPTNO AVG(SAL)
---------- ----------
30 1566.66667
20 2175
10 2916.66667
6> 1 select deptno,job,sum(sal)
2 from emp
3 group by deptno,job
4 order by 1
-------------------------
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
20 ANALYST 6000
20 CLERK 1900
20 MANAGER 2975
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
7> SQL> select deptno,avg(sal)
2 from emp
3 group by deptno
4 having avg(sal)>2000;
DEPTNO AVG(SAL)
---------- ----------
20 2175
10 2916.66667
8> SQL> /*
SQL> group by的增強
SQL> group by deptno,job
SQL> +
SQL> group by deptno
SQL> +
SQL> group by null
SQL> =
SQL> group by rollup(deptno,job)
SQL>
SQL> group by rollup(a,b)
SQL> =
SQL> group by a,b
SQL> +
SQL> group by a
SQL> +
SQL> group by null
SQL> */
-----------------------------------
SQL> select deptno,job,sum(sal)
2 from emp
3 group by rollup(deptno,job);
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
10 8750
20 CLERK 1900
20 ANALYST 6000
20 MANAGER 2975
20 10875
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 9400
29025
已選擇13行。
9> break on 列名 根據列值的範圍分割輸出結果
SQL> break on deptno skip 2
SQL> select deptno,job,sum(sal)
2 from emp
3 group by rollup(deptno,job);
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
MANAGER 2450
PRESIDENT 5000
8750
20 CLERK 1900
ANALYST 6000
MANAGER 2975
10875
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 CLERK 950
MANAGER 2850
SALESMAN 5600
9400
29025
已選擇13行。
-----------------------------------------------------------------------------------------
SQL> break on null
SQL> /
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
10 8750
20 CLERK 1900
20 ANALYST 6000
20 MANAGER 2975
20 10875
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 9400
29025
1.基本命令
1> show user 當前使用者
2> select * from tab; 當前使用者下的表
tab: 資料字典(表)
3> desc 表名-----------查看錶結構
4> set linesize 120 --設定行寬
5> col ename for a8 --設定行寬
col sal for 9999
6> c命令
SQL> select *
2 form emp;
form emp
*
第 2 行出現錯誤:
ORA-00923: 未找到要求的 FROM 關鍵字
SQL> --c 命令
SQL> 2
2* form emp
SQL> c /form/from
2* from emp
SQL> /
7> --DISTINCT 去掉重複記錄
select DISTINCT deptno,job from emp;
--DISTINCT作用於後面所有的列
8> --連線符
concat('Hello',' World')
9> --dual:偽表
select 3+2 from dual;
3+2
----------
5
10> save c:\a.sql -----儲存位sql指令碼
已建立 file c:\a.sql
@c:\a.sql ---------執行sql指令碼
2.過濾和排序
1> --字元大小寫敏感
2> --日期格式敏感
select sysdate from dual
SYSDATE
--------------
19-6月 -13
-----------------預設格式-----------------
SQL> select *
2 from v$nls_parameters;
PARAMETER VALUE
------------------------------ ----------------------------------------------------------------
NLS_LANGUAGE SIMPLIFIED CHINESE
NLS_TERRITORY CHINA
NLS_CURRENCY ￥
NLS_ISO_CURRENCY CHINA
NLS_NUMERIC_CHARACTERS .,
NLS_CALENDAR GREGORIAN
NLS_DATE_FORMAT DD-MON-RR
NLS_DATE_LANGUAGE SIMPLIFIED CHINESE
NLS_CHARACTERSET ZHS16GBK
NLS_SORT BINARY
NLS_TIME_FORMAT HH.MI.SSXFF AM
PARAMETER VALUE
------------------------------ ----------------------------------------------------------------
NLS_TIMESTAMP_FORMAT DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY ￥
NLS_NCHAR_CHARACTERSET AL16UTF16
NLS_COMP BINARY
NLS_LENGTH_SEMANTICS BYTE
NLS_NCHAR_CONV_EXCP FALSE
已選擇19行。
------------------------修改預設格式---------------------
SQL> alter session set NLS_DATE_FORMAT='yyyy-mm-dd';
會話已更改。
3> between and 在...之間 (小值在前 大值在後)
SQL> --查詢薪水1000~2000之間的員工
SQL> select *
2 from emp
3 where sal between 1000 and 2000;
4> in 在集合中 not in 不在集合中
SQL> --查詢部門號是10和20的員工
SQL> select *
2 from emp
3 where deptno in (10,20);
5> like 模糊查詢 %(任意多個) _(任意一個)
--查詢名字是4個字的員工
select *
from emp
where ename like '____';
-------------------------------------
--查詢名字中含有下劃線的員工
select *
from emp
where ename like '%\_%' escape '\';
6> 排序
SQL> select *
2 from emp
3 order by sal;
SQL> --a命令 append
SQL> a desc
3* order by sal desc
SQL> /
-------------------------------------------------
--order by後面+列名 表示式 別名 序號
select *
2 from emp
3 order by comm desc
4* nulls last -----空值最後
3.單行函式
1> --NULLIF(a,b) 當a=b時, 返回null，否則返回a
SQL> select nullif('abc','abcd') from dual;
NUL
---
abc
2> --COALESCE :從左往右找到第一個不為null的值
select comm,sal,COALESCE(comm,sal) from emp;
3> case...end
SQL> --條件表示式
SQL> --漲工資，總裁1000 經理800 其他400
SQL> select ename,job,sal 漲前薪水,
2 case job when 'PRESIDENT' then sal+1000
3 when 'MANAGER' then sal+800
4 else sal+400
5 end 漲後薪水
6 from emp;
4> SQL> select ename,job,sal 漲前薪水,
2 decode(job,'PRESIDENT',sal+1000,
3 'MANAGER',sal+800,
4 sal+400) 漲後薪水
5 from emp;
4.組函式
1> --工資總額
SQL> select sum(sal) from emp;
2> --人數
SQL> select count(*) from emp;
3> --平均工資
SQL> select sum(sal)/count(*) 一,avg(sal) 二 from emp;
4> --平均獎金
SQL> select sum(comm)/count(*) 一, sum(comm)/count(comm) 二, avg(comm) 三
2 from emp;
一 二 三
---------- ---------- ----------
157.142857 550 550
5> --分組資料
SQL> --求每個部門的平均工資
SQL> select deptno,avg(sal)
2 from emp
3 group by deptno;
DEPTNO AVG(SAL)
---------- ----------
30 1566.66667
20 2175
10 2916.66667
6> 1 select deptno,job,sum(sal)
2 from emp
3 group by deptno,job
4 order by 1
-------------------------
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
20 ANALYST 6000
20 CLERK 1900
20 MANAGER 2975
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
7> SQL> select deptno,avg(sal)
2 from emp
3 group by deptno
4 having avg(sal)>2000;
DEPTNO AVG(SAL)
---------- ----------
20 2175
10 2916.66667
8> SQL> /*
SQL> group by的增強
SQL> group by deptno,job
SQL> +
SQL> group by deptno
SQL> +
SQL> group by null
SQL> =
SQL> group by rollup(deptno,job)
SQL>
SQL> group by rollup(a,b)
SQL> =
SQL> group by a,b
SQL> +
SQL> group by a
SQL> +
SQL> group by null
SQL> */
-----------------------------------
SQL> select deptno,job,sum(sal)
2 from emp
3 group by rollup(deptno,job);
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
10 8750
20 CLERK 1900
20 ANALYST 6000
20 MANAGER 2975
20 10875
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 9400
29025
已選擇13行。
9> break on 列名 根據列值的範圍分割輸出結果
SQL> break on deptno skip 2
SQL> select deptno,job,sum(sal)
2 from emp
3 group by rollup(deptno,job);
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
MANAGER 2450
PRESIDENT 5000
8750
20 CLERK 1900
ANALYST 6000
MANAGER 2975
10875
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 CLERK 950
MANAGER 2850
SALESMAN 5600
9400
29025
已選擇13行。
-----------------------------------------------------------------------------------------
SQL> break on null
SQL> /
DEPTNO JOB SUM(SAL)
---------- --------- ----------
10 CLERK 1300
10 MANAGER 2450
10 PRESIDENT 5000
10 8750
20 CLERK 1900
20 ANALYST 6000
20 MANAGER 2975
20 10875
30 CLERK 950
30 MANAGER 2850
30 SALESMAN 5600
DEPTNO JOB SUM(SAL)
---------- --------- ----------
30 9400
29025
已選擇13行。
待續.................