如何学好PL/SQL
发布网友
发布时间：2022-04-29 21:54
共5个回答
懂视网
时间：2022-04-30 02:15
$147 $5
SELECT c.customer_id cust_id, o.order_id ord_id, c.gender
FROM customers c
JOIN orders o
ON c.customer_id = o.customer_id ;
CUST_ID ORD_ID G
--------- --------- -
$147 $2450 F
$147 $2425 F
$147 $2385 F
$147 $2366 F
$147 $2396 F
$148 $2451 M
$148 $2426 M
$148 $2386 M
$148 $2367 M
3.Group by语句：
SELECT c.customer_id, COUNT(o.order_id) AS orders_ct
FROM customers c
JOIN orders o
ON c.customer_id = o.customer_id
WHERE gender = ‘F‘
GROUP BY c.customer_id;
CUSTOMER_ID ORDERS_CT
----------- ---------
$123 $1
$147 $5
$107 $4
$154 $1
$169 $1
$104 $4
$105 $4
$146 $5
$156 $1
$166 $1
$103 $4
11 rows selected.
4.Select列表：
SELECT c.customer_id,
c.cust_first_name || ‘‘ || c.cust_last_name,
(SELECT e.last_name
FROM hr.employees e
WHERE e.employee_id = c.account_mgr_id) acct_mgr
FROM oe.customers c;
CUSTOMER_ID C.CUST_FIRST_NAME||‘‘||C.CUST_LAST_NAME ACCT_MGR
----------- ---------------------------------------- -------------------------
$147 IshwaryaRoberts Russell
$148 GustavSteenburgen Russell
$149 MarkusRampling Russell
$150 GoldieSlater Russell
$151 DivineAykroyd Russell
$152 DieterMatthau Russell
$153 DivineSheen Russell
$154 FredericGrodin Russell
$155 FredericoRomero Russell
5.INSERT语句：
INSERT INTO hr.jobs
(job_id, job_title, min_salary, max_salary)
VALUES
(‘IT_PM‘, ‘Project Manager‘, 5000, 11000);
1 row created.
SQL> commit;
Commit complete.
6.多表查询：
SQL> select * from large_customers;
no rows selected
SQL> select * from medium_customers;
no rows selected
SQL> select * from small_customers;
no rows selected
INSERT ALL WHEN sum_orders < 10000 THEN INTO small_customers WHEN sum_orders >= 10000 AND sum_orders < 100000 THEN INTO medium_customers ELSE INTO large_customers
SELECT customer_id, SUM(order_total) sum_orders
FROM orders
GROUP BY customer_id;
plsqL复习
标签：oracle
热心网友
时间：2022-04-29 23:23
当然你也要针对这种语言的特征来学习，就pl/sql而言，它是oracle特有的，但你要记住“天下武功出少林”，你首先要找出他与他的祖先sql和t-sql的异同，这样不仅能学好pl/sql而且还能在学习的过程中复习到其他两种语言，你可以先找一本pl/sql的语法书，然后熟练其中的内容，记得要在电脑上实战练习一下，学习计算机切记不可脱离实践。基本语法掌握以后，你并可以找点项目来实践一下，网上的经典试题很多，比如“ATM银行系统”“图书管理系统”等等，这些题相对简单，如果遇到什么问题你可以到百度知道上来发问，把问题解决了你才能真正提高。
其实“背”也是学习所有语言的秘诀。
祝你成功 ^ ^)
热心网友
时间：2022-04-30 00:41
热心网友
时间：2022-04-30 02:16
就是一边用一边学的
这样比较好
热心网友
时间：2022-04-30 04:07
另 pl/sql7.0有中文版,里有一个中文件帮助手册.
这样就开始了/
