connect by prior 是結構化查詢中用到的,其基本文法是:select ... from tablename start with 條件1connect by prior 條件2where 條件3;項目中例子:省市級聯中根據省取市:select t.* from website_area t start with t.parent_id = 330000 connect by prior t.area_id = t.parent_id and t.status=1 order by
1、根據表NEWPRODUCTS的PRODUCT_ID欄位是否匹配來updates表PRODUCTS的資訊:SQL> MERGE INTO products p 2 USING newproducts np 3 ON (p.product_id = np.product_id) 4 WHEN MATCHED THEN 5 UPDATE 6 SET p.product_name = np.product_name, 7 p.category =
set serveroutput on;標量:declare v_name myTable.name%type;beginselect name into v_ name from myTable where id = &aaaaa;dbms_output.put_line('名字:'||v_ name);exceptionwhen no_data_foundthen dbms_output.put_line('沒有編號');end;複合:declare type
table表有id、name兩個欄位:有資料:1、a;2、b;3、c;4,c;5、bselect distinct name from table; ——>name a b cselect distinct name, id from table ——>id name 1 a 2 b 3 c 4 c 5 b(id與name都相同的才會被排除)select id, distinct name from table
oracle 邏輯備份命令EXP/IMP參數參考手冊 協助命令:exp help=yExport: Release 10.2.0.1.0 - Production on Thu Jul 20 10:39:50 2006 Copyright (c) 1982, 2005, Oracle. All rights reserved. You can let Export prompt you for parameters by entering the EXPcommand followed
在 SQLPLUS中,直接用 DESC[ribe] tablename 即可。可要是在外部應用程式調用查看ORACLE中的表結構時,這個命令就不能用了。只能用下面的語句代替:看欄位名與資料類型 select * from cols WHERE TABLE_name=upper('table_name'); (user_tab_columns縮寫cols)查看全部列select * from user_tab_columns where table_name = upper(‘tablename’
HAVING 與 WHERE 類似,可用來決定選擇哪個記錄。在使用 GROUP BY對這些記錄分組後,HAVING 會決定應顯示的記錄,不同的是where對分組前的結果集條件過濾,而having對分組後的結果集過濾;having何以跟彙總函式,而where則不能。 現在舉個例子:範例:要求顯示平均工資大於2000的部門編號和平均工資Select deptno,avg(sal) from emp where avg(sal)>2000 group by