一、利用游标实现循环嵌套

在对oracle数据进行操作时我们会经常碰到循环甚至循环嵌套的情况。这个时候游标的作用就体现出来了。

DECLAREvId NUMBER(19);vDate DATE;--a表游标定义CURSOR a_cursor ISSELECT DISTINCT o.employeeId FROM operations o WHERE o.employeeId IS NULL ORDER BY 1;--b表游标定义CURSOR b_cursor(eid number) ISSELECT DISTINCT trunc(o.startDate) startDateFROM operations o WHERE o.employeeId = eid AND o.employeeId IS NULLORDER BY 1;
BEGIN FOR a_cur IN a_cursor LOOPvId := a_cur.receiverid;FOR b_cur IN b_cursor(vId) LOOPvDate := b_cur.startlifecycle;Employee_operationSettlement(vDate,vId);--做操作END LOOP;END LOOP;
END;

二、灵活使用%ROWTYPE

DECLARE   V_employee employees%ROWTYPE 
BEGIN   SELECT * INTO V_operationFROM employees e WHERE e.code = '9999';--插入数据INSERT INTO employees (code,name,age)VALUES ('9998',V_operation.name,V_operation.age);--修改数据UPDATE employees tSET ROW = V_employeeWHERE e.code = '9999';
END; 

三、根据主键表名查询存在外键关联的表名和字段名，并查询指定主键值在外键表中关联的数据条目

DECLAREVSql VARCHAR2(256);VCount NUMBER;CURSOR a_cursor isSELECT DISTINCT B.TABLE_NAME tableName,c.column_name columnNameFROM DBA_CONSTRAINTS A, DBA_CONSTRAINTS B, USER_CONS_COLUMNS C  WHERE A.CONSTRAINT_NAME = B.R_CONSTRAINT_NAME  AND B.CONSTRAINT_TYPE = 'R'  AND a.TABLE_NAME = 'OPERATIONROLES'AND c.constraint_name = b.constraint_nameAND (instr(B.TABLE_NAME,'_')=0 OR instr(B.TABLE_NAME,'_CS')>0)--表名过滤条件（不包含‘_’,或包含‘_CS’）ORDER BY 1,2;
BEGIN FOR a_cur IN a_cursor LOOPVSql := 'SELECT count('||a_cur.columnName||') FROM '||a_cur.tableName||' WHERE '||a_cur.columnName||' = 40010';--指定值为（40010）EXECUTE IMMEDIATE VSql INTO VCount;IF VCount > 0 THEN --只看存在数据的条目DBMS_OUTPUT.put_line(VSql||'____'||VCount);--输出（SQl____对应数据条数）END IF;END LOOP;
END;

四、递归查询

--寻根
SELECT o.* 
FROM PartyRoleAssociations p,ORGANIZATIONUNITS o
WHERE p.partyroleid = o.id
AND LEVEL = 1 --层级
START WITH p.associationpartyroleid = '131000755'--开始子节点ID
CONNECT BY p.associationpartyroleid = PRIOR p.partyroleid;---自顶向下
SELECT o.* 
FROM PartyRoleAssociations p,ORGANIZATIONUNITS o
WHERE p.associationpartyroleid = o.id
START WITH p.associationpartyroleid = '131000161'--父级节点ID
CONNECT BY PRIOR p.associationpartyroleid = p.partyroleid;

五、通过group by和wm_concat来快速定位数据

SELECT o.employeeId, wm_concat(o.name) --行列转换
FROM operations o 
GROUP BY o.employeeId;

六、依照模板数据快速插入数据，特别适用于表字段特别多的情况

DECLARE   V_employee employees%ROWTYPE;CURSOR a_cursor IS SELECT * FROM employees;
BEGIN   SELECT * INTO V_operationFROM employees e WHERE e.code = '9999';--1INSERT INTO employees (code,name,age)VALUES ('9998',V_operation.name,V_operation.age);--2V_operation.code := '9997';V_operation.name := '张三';INSERT INTO employeesVALUES V_operation;--3FOR a_cur IN a_cursor LOOPIF a_cur.code = '9999' THENa_cur.code := '9996';a_cur.name := '李四';INSERT INTO employees VALUES a_cur;END IF;END LOOP;--4INSERT INTO Employees(code, Name, age)SELECT '9995' code, --值,别名（可忽略）'王五' name,ageFROM Employees eWHERE e.code = '9999';
END; 

七、快速定位存储过程

在项目开发中，经常遇到这样的情况，现在需要改动一个表、函数或者存储过程（简称为对象），但是不知道这个对象被哪些函数、定时任务或存储过程调用，便可利用以下SQL解。

SELECT DISTINCT t.type "类型", t.name "名称"
FROM User_Source t
WHERE t.type = 'PROCEDURE' --FUNCTION(函数),PROCEDURE(存储过程),TRIGGER(触发器)
AND LOWER(t.text) LIKE '%string%' --string英文小写
UNION ALL
SELECT DISTINCT 'JOB' "类型", j.JOB_NAME "名称" FROM user_scheduler_jobs j
WHERE LOWER(j.JOB_ACTION) LIKE '%string%';--查询定时任务ACTION中是否包含

八、中断ORACLE的JOB

网上查了一下，大多是通过dba_jobs_running去查SID，发现查不到，后来发现是可以通过dba_scheduler_running_jobs去查SID的

SELECT t.session_id SID FROM dba_scheduler_running_jobs t;
SELECT SID,SERIAL#  FROM V$Session WHERE SID = '1018';
ALTER SYSTEM KILL SESSION '1018,127';