oracle SQL集锦

下面的语句都是本人整理出的，并且都在oracle XE上测试通过。下边的函数都没有做说明，相信大家都知道怎么用了，呵呵。

1 普通的查询语句，例如：
SELECT last_name,department_id FROM employees;
2 查询视图
SELECT employee_id,last_name,job_title,department_name,country_name,
region_name FROM emp_details_view;
3 更换列名查询
SELECT employee_id"EmployeeID number ",last_name"Employeelastname",
first_name"Employeefirstname" FROM employees;
4 联接查询
自然联接：要求两个表中的公共列必须有相同的名称和结构类型，否则报错。
SELECT employee_id,last_name,first_name,department_id,
department_name,manager_id FROM employeesNATURAL JOIN departments;
查询三张或以上表时用USING，前提是用来连接两张表的列必须名称相同。
SELECT e.employee_id,e.last_name,e.first_name,e.manager_id,department_id,
d.department_name,d.manager_id FROM employeese
JOIN departmentsdUSING(department_id);
联接时加上WHERE子句。
SELECT e.employee_id,e.last_name,e.first_name,e.department_id,
d.department_name,d.manager_id,d.location_id,l.country_id FROM employeese
JOIN departmentsd ON e.department_id = d.department_id
JOIN locationsl ON d.location_id = l.location_id
WHERE l.location_id = 1700 ;
自我联接：
SELECT e.employee_idemp_id,e.last_nameemp_lastname,m.employee_idmgr_id,
m.last_namemgr_lastname
FROM employeese
JOIN employeesm ON e.manager_id = m.employee_id;
LEFT OUTER JOIN ：左表中所有的记录即使在右表中没有联接的都会被查询出来。
SELECT e.employee_id,e.last_name,e.department_id,d.department_name
FROM employeese LEFT OUTER JOIN departmentsd
ON (e.department_id = d.department_id);
RIGHT OUTER JOIN ：右表中所有的记录即使在左表中没有联接的都会被查询出来。
SELECT e.employee_id,e.last_name,e.department_id,d.department_name
FROM employeese RIGHT OUTER JOIN departmentsd
ON (e.department_id = d.department_id);
FULL OUTER JOIN ：左右表中的记录全部被查询出来。
SELECT e.employee_id,e.last_name,e.department_id,d.department_name
FROM employeese FULL OUTER JOIN departmentsd
ON (e.department_id = d.department_id);

5 绑定变量查询：Oracle将已解析、已编译的SQL连同其他内容存储在共享池中，这是SGA中一个非常重要的存储结构（内存结构主要分为SGA和PGA）。而绑定变量查询在Oracle里执行时只编译一次，随后就会把这个查询计划存储在一个共享池中以便重用，即所谓的软解析。具体的使用方法如下：
SELECT * FROM employees WHERE employee_id = :employee_id
6 查询虚拟列：所谓的虚拟列在Oracle里类似表格的列，但并非存储在表中。查询虚拟列时将返回一个值，因此它又类似与函数。Oracle里的虚拟列有：ROWNUM,SYSDATE, and USER 。eg：
SELECT SYSDATE"NOW" FROM DUAL;
SELECT USER FROM DUAL;
SELECT employee_id,hire_date,SYSDATE FROM employees WHERE ROWNUM < 10 ;
7 带函数查询：
UsingNumericFunctions：
SELECT employee_id, ROUND (salary / 30 , 2 )"Salaryper day " FROM employees;
SELECT employee_id,TRUNC(salary / 30 , 0 )"Salaryper day " FROM employees;
SELECT employee_id,MOD(employee_id, 2 ) FROM employees;
Using Character Functions：
SELECT employee_id, UPPER (last_name), LOWER (first_name) FROM employees;
SELECT employee_id,INITCAP(first_name),INITCAP(last_name) FROM employees;
SELECT employee_id, RTRIM (first_name) || ' ' || LTRIM (last_name) FROM employees;
SELECT employee_id,TRIM(last_name) || ' , ' || TRIM(first_name) FROM employees;
SELECT employee_id,RPAD(last_name, 30 , ' ' ),first_name FROM employees;
SELECT employee_id,SUBSTR(last_name, 1 , 10 ) FROM employees;
SELECT LENGTH(last_name) FROM employees;
SELECT employee_id, REPLACE (job_id, ' SH ' , ' SHIPPING ' ) FROM employees
WHERE SUBSTR(job_id, 1 , 2 ) = ' SH ' ;
UsingDateFunctions：
SELECT employee_id,TRUNC(MONTHS_BETWEEN(SYSDATE,HIRE_DATE))"MonthsEmployed"
FROM employees;
SELECT employee_id,EXTRACT( YEAR FROM hire_date)" Year Hired" FROM employees;
SELECT EXTRACT( YEAR FROM SYSDATE) || EXTRACT( MONTH FROM SYSDATE) ||
EXTRACT( DAY FROM SYSDATE)" Current Date" FROM DUAL;
SELECT employee_id,hire_date,ADD_MONTHS(hire_date, 3 ) FROM employees;
SELECT employee_id,hire_date,LAST_DAY(hire_date)"Last day of month "
FROM employees;
SELECT SYSTIMESTAMP FROM DUAL;
UsingConversionFunctions：
SELECT TO_CHAR(SYSDATE, ' DD-MON-YYYYAD ' )"Today" FROM DUAL;
SELECT TO_CHAR(SYSDATE, ' FMMonthDDYYYY ' )"Today" FROM DUAL;
SELECT TO_CHAR(SYSDATE, ' MM-DD-YYYYHH24:MI:SS ' )"Now" FROM DUAL;
SELECT hire_date,TO_CHAR(hire_date, ' DS ' )"ShortDate" FROM employees;
SELECT hire_date,TO_CHAR(hire_date, ' DL ' )" Long Date" FROM employees;
SELECT TO_CHAR(EXTRACT( YEAR FROM SYSDATE)) ||
TO_CHAR(EXTRACT( MONTH FROM SYSDATE), ' FM09 ' ) ||
TO_CHAR(EXTRACT( DAY FROM SYSDATE), ' FM09 ' )" Current Date" FROM DUAL;
SELECT TO_CHAR( CURRENT_DATE , ' DD-MON-YYYYHH24:MI:SS ' )" Current Date" FROM DUAL;
SELECT TO_CHAR(salary, ' $99,999.99 ' )salary FROM employees;
SELECT TO_NUMBER( ' 1234.99 ' ) + 500 FROM DUAL;
SELECT TO_NUMBER( ' 11,200.34 ' , ' 99G999D99 ' ) + 1000 FROM DUAL;
SELECT TO_DATE( ' 27-OCT-98 ' , ' DD-MON-RR ' ) FROM DUAL;
SELECT TO_DATE( ' 28-Nov-0514:10:10 ' , ' DD-Mon-YYHH24:MI:SS ' ) FROM DUAL;
SELECT TO_DATE( ' January15,2006,12:00A.M. ' , ' Monthdd,YYYY,HH:MIA.M. ' )
FROM DUAL;
SELECT TO_TIMESTAMP( ' 10-Sep-0514:10:10.123000 ' , ' DD-Mon-RRHH24:MI:SS.FF ' )
FROM DUAL;
UsingAggregateFunctions：
SELECT COUNT ( * )"Employee Count " FROM employees WHERE manager_id = 122 ;
SELECT COUNT ( * )"Employee Count ",manager_id FROM employees
GROUP BY manager_id ORDER BY manager_id
SELECT COUNT (commission_pct) FROM employees;
SELECT COUNT ( DISTINCT department_id) FROM employees;
SELECT MIN (salary), MAX (salary), AVG (salary),job_id FROM employees
GROUP BY job_id ORDER BY job_id;
SELECT RANK( 2600 )WITHIN GROUP
( ORDER BY salary DESC )"Rank of $ 2 , 600 amongclerks"
FROM employees WHERE job_id LIKE ' %CLERK ' ;
SELECT job_id,employee_id,last_name,salary,DENSE_RANK() OVER
(PARTITION BY job_id ORDER BY salary DESC )"SalaryRank(Dense)"
FROM employees WHERE job_id = ' SH_CLERK ' ;
SELECT employee_id,salary,hire_date,STDDEV(salary)
OVER ( ORDER BY hire_date)"StdDeviation of Salary"
FROM employees WHERE job_id = ' ST_CLERK ' ;
Using NULL ValueFunctions：
SELECT commission_pct,NVL(commission_pct, 0 ) FROM employees;
SELECT phone_number,NVL(phone_number, ' MISSING ' ) FROM employees;
SELECT employee_id,last_name,commission_pct,salary,
NVL2(commission_pct,salary + (salary * commission_pct),salary)income
FROM employees;
UsingConditionalFunctions：
SELECT employee_id,hire_date,salary,
CASE WHEN hire_date < TO_DATE( ' 01-JAN-90 ' ) THEN salary * 1.20
WHEN hire_date < TO_DATE( ' 01-JAN-92 ' ) THEN salary * 1.15
WHEN hire_date < TO_DATE( ' 01-JAN-94 ' ) THEN salary * 1.10
ELSE salary * 1.05 END "RevisedSalary"
FROM employees;
SELECT employee_id,job_id,salary,
DECODE(job_id, ' PU_CLERK ' ,salary * 1.05 ,
' SH_CLERK ' ,salary * 1.10 ,
' ST_CLERK ' ,salary * 1.15 ,
salary)"RevisedSalary"
FROM employees;