過濾和排序
SQL> --查詢10號部門的員工
SQL> select *
2 from emp
3 where deptno=10;
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- -------- --------- ---------- -------------- ----- ---------- ----------
7782 CLARK MANAGER 7839 09-6月 -81 2450 10
7839 KING PRESIDENT 17-11月-81 5000 10
7934 MILLER CLERK 7782 23-1月 -82 1300 10
SQL> --字符串大小寫敏感
SQL> --查詢名叫KING的員工
SQL> select *
2 from mep
3 /
from mep
*
第 2 行出現錯誤:
ORA-00942: 表或視圖不存在
SQL> ed
已寫入 file afiedt.buf
1 select *
2 from emp
3* where ename='KING'
SQL> /
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- -------- --------- ---------- -------------- ----- ---------- ----------
7839 KING PRESIDENT 17-11月-81 5000 10
SQL> ed
已寫入 file afiedt.buf
1 select *
2 from emp
3* where ename='King'
SQL> /
未選定行
SQL> --日期格式敏感
SQL> --查詢入職日期是17-11月-81的員工
SQL> select *
2 from emp
3 where hiredate='17-11月-81';
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO
---------- -------- --------- ---------- -------------- ----- ---------- ----------
7839 KING PRESIDENT 17-11月-81 5000 10
SQL> ed
已寫入 file afiedt.buf
1 select *
2 from emp
3* where hiredate='1981-11-17'
SQL> /
where hiredate='1981-11-17'
*
第 3 行出現錯誤:
ORA-01861: 文字與格式字符串不匹配
SQL> --修改日期格式
SQL> select * from v$nls_parameters;
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_LANGUAGE
SIMPLIFIED CHINESE
NLS_TERRITORY
CHINA
NLS_CURRENCY
￥
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_ISO_CURRENCY
CHINA
NLS_NUMERIC_CHARACTERS
.,
NLS_CALENDAR
GREGORIAN
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_DATE_FORMAT
DD-MON-RR
NLS_DATE_LANGUAGE
SIMPLIFIED CHINESE
NLS_CHARACTERSET
ZHS16GBK
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_SORT
BINARY
NLS_TIME_FORMAT
HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT
DD-MON-RR HH.MI.SSXFF AM
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_TIME_TZ_FORMAT
HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT
DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY
￥
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_NCHAR_CHARACTERSET
AL16UTF16
NLS_COMP
BINARY
NLS_LENGTH_SEMANTICS
BYTE
PARAMETER
----------------------------------------------------------------
VALUE
----------------------------------------------------------------
NLS_NCHAR_CONV_EXCP
FALSE
已選擇 19 行。
SQL> set linesize 200
SQL> select * from v$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。
SQL> alter session set NLS_DATE_FORMAT='yyyy-mm-dd';
會話已更改。
SQL> select *
2 from emp
3 where hiredate='1981-11-17';
EMPNO ENAME JOB MGR HIREDATE SAL COMM DEPTNO