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SQLÓï¾äPART9

Group functions
SELECT [column,] group_function(column) ... from table [WHERE condition] [GROUP BY group_by_expression] [ORDER BY column];
e.g.:
SELECT department_id, job_id, SUM(salary), COUNT(employee_id) from employees GROUP BY department_id, job_id ;
SELECT [column,] group_function(column)... from table [WHERE condition] [GROUP BY group_by_expression]
[HAVING having_expression] [ORDER BY column];
GROUP BY with ROLLUP and CUBE Operators
1. Use ROLLUP or CUBE with GROUP BY to produce superaggregate rows by cross-referencing columns.
2. ROLLUP grouping produces a result set containing the regular grouped rows and the subtotal values.
3. CUBE grouping produces a result set containing the rows from ROLLUP and cross-tabulation rows.
SELECT [column,] group_function(column). . .from table [WHERE condition] [GROUP BY [ROLLUP] group_by_expression] [HAVING having_expression];[ORDER BY column];
//ROLLUP is an extension to the GROUP BY clause Use the ROLLUP operation to produce cumulative
aggregates, such as subtotals.
e.g. :
select nmoduleinfoid, ndocsortid, salary from t1;
1    1    1000
1    2    2100
1    3    1300
2    4    1400
select nmoduleinfoid, ndocsortid, sum(salary) from t1 group by rollup(nmoduleinfoid, ndocsortid);
1    1    1000
1    2    2100
1    3    1300
1          4400
2    4    1400
2          1400
            5800
SELECT [column,] group_function(column)... from table [WHERE condition] [GROUP BY [CUBE] group_by_expression] [HAVING having_expression] [ORDER BY column];
// CUBE is an extension to the GROUP BY clause. You can use the CUBE operator to produce cross-tabulation


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ORACLE PL/SQL°ü(package)ѧϰ±Ê¼Ç

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CREATE [OR REPLACE] PACKAGE package_name {IS | AS}
Procedure_name | function_name | variable_declaration | type_def ......

ORACLE PL/SQL ´¥·¢Æ÷(trigger)ѧϰ±Ê¼Ç

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ORACLE PL/SQL ¶ÔÏó(object)ѧϰ±Ê¼Ç(¶þ)

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CREATE OR REPLACE TYPE Obj1 AS OBJECT (
f1 NUMBER,
f2 VARCHAR2(10),
f3 DATE
);
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CREATE OR REPLACE TYPE Obj2 AS OBJECT (
f1 DATE,
f2 CHAR(1)
);
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CREATE OR REPLACE TYPE Obj3 AS OBJECT (
a Obj1,
b Obj2
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OBJ3ÒÀÀµÓÚOBJ ......

SQLÓï¾äPART1

Oracle SQL(partI)
Data manipulation language(DML): select, insert, update, delete, merge.
Data definition language(DDL): create, alter, drop, rename, truncate, comment
Data control language(DCL): grant, revoke
Transaction control: commit, rollback, savepoint
Arithmetic Expressions:
+, -, *, / ......

SQLÓï¾äPART2

Subquery: (single-row subqueries and multi-rows subqueries).
select select_list
from table
where expr operator (select select_list from table);
single-row subqueries operator: =, >, >=, <, <=, <>
e.g.:
1. select department_id, min(salary) from employees group by department_id ......
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