Skill-building Courses Business Analysis Lesson 3 Problem Solving

Transcription

1 Skill-building Courses Business Analysis Lesson 3 Problem Solving

2 Review Software Development Life Cycle/Agile/Scrum Learn best practices for collecting and cleaning data in Excel to ensure accurate analysis results. Transform and rearrange columns and rows within spreadsheets to prepare data for analysis. Gain insight into data analysis by manipulating data formats. Execute Excel aggregation commands (SUM, AVERAGE, COUNT, etc.) and their conditional variants (COUNTIF, COUNTBLANKS, etc.) to summarize data sets.

3 Use the VLOOKUP and HLOOKUP functions to manipulate data sets. Look up values in other tables using the functions INDEX and MATCH. Summarize data using pivot tables.

4 Looking 2016 How many schools are in the data set? 47 How many staff members are in the data set? (but unique ID 10002) Who share the same ID? Edwin; Kate Armando; Emersyn Eastonl Xzavier

5 Any staff in multiple schools? If so, which ones? CAMILLE JOHNSON Newfoundland Elementary School 1 CAMILLE JOHNSON Rottweiler Middle School 1 CAMILLE SMITH Barbet Elementary School 1 CAMILLE SMITH Chihuahua Middle School 1 CAMILLE SMITH Drever Elementary School 1 KOLE JOHNSON Beagle Elementary School 1 KOLE JOHNSON Retriever Middle School 1 KOLE SMITH Dachschund Middle School 1 KOLE SMITH Pomeranian Elementary School 1 PAULA WILLIAMS Chow Middle School 1 PAULA WILLIAMS Pomeranian Elementary School 1 SUTTON NICHOLS Airedale High School 1 SUTTON NICHOLS Beagle Elementary School 1

6 How many members are in each role? role Count of Administrator 899 Counselor 1698 Support Professional 2699 Teacher ) School ID 和 School Name 数据没有问题 2) Staff ID 少于 unique Staff Name== 需要返回 database 修改相应人员的 ID 3) 那些人是 Teacher/Administrator/Counselor?

7 Skill-building Courses Business Analysis Lesson 4 Intro to SQL

8 Looking 2017 有哪些学校在 2017 年的学校目录里, 但是却不在 2016 年的记录里?( 可能是 2017 年新建的学校 ) Labrador Learners Elementary School Shepard Middle School for STEM Siberian Husky Charter Pug Charter Bulldog Charter Great Dane Elementary Akita Middle Terrier High Lecture 4: 其实只有 (8-2=)6 个学校是新建的 推断 : 这八所学校不都是 2017 新建的 ( 因为 2017 年不同的 school name 有 51 个 2016 年不同的 school name 有 47 个所以如果都是新建的话, 应该只有 4 个是本题答案 )

9 再提问 : 有没有学校是 2016 年拆了的?( 如果有的话, 就可以把它们从数据库中删除, 节省内存 ) Labrador Elementary School Maltese High School Shepard Middle School Lecture 4: 其实只有两个学校是真正拆除了的 Maltese High School Yorkshire Middle School Yorkshire Middle School 事情不是如此简单, 应该需要检查有那些学校 2017 年换了名字

10 哪些学校换了新名字? Labrador Elementary School (2016) Labrador Learners Elementary School (2017) Shepard Middle School (2016) Shepard Middle School for STEM (2017) 小结 ( 这些都是我们刚才通过数据分析得出的结果 ): 1)2016 年有两所学校拆除了 ( 可以从 database 中除名,SQL: delete) 2) 有两所学校改名了 ( 需要在 database 中修改名字, 但是他们的 ID2016 年就存在,SQL: update) 3)2017 年有六所新建的学校 ( 需要在 database 中添加这些学校并 assign school ID, SQL: insert) 4) 有些老师在不同学校任教 5) 有些老师可能担任多个角色 ( 影响到资源的分配 ) 6) 共用 ID 的人需要解决

11 THIS CLASS: Practice the fundamentals of Structured Query Language (SQL). Collect data using standard SQL commands Filter data using advanced SQL Obtain data by creating relationships between tables using Joins. Gather filtered data using SQL conditional operators

12 What is SQL? SQL is a standard language for accessing and manipulating databases. SQL stands for Structured Query Language SQL lets you access and manipulate databases SQL is an ANSI (American National Standards Institute) standard

13 一个简单的例子 数据库 : 我们需要解决的问题 : 找出既会 VB 又会 PHP 的人 答案 ( 使用 SQL 语言 ): SELECT 员工 FROM [Table] WHERE 员工 IN (SELECT 员工 FROM [Table] WHERE 技能 = VB AND 技能 = PHP ) ID 员工 技能 1 1 VB 2 1 PHP 3 1 ASP 4 2 PHP 5 3 ASP 6 4 VB 7 4 ASP

14 主键和外键 :Keys and Foreign Keys Company CName StockPrice Country Key GizmoWorks 25 USA Canon 65 Japan Hitachi 15 Japan SingleTouch $ Photography Canon MultiTouch $ Household Hitachi Foreign key

15 SELECT-FROM-WHERE SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT * FROM WHERE category= Gadgets 特别提示 : 注意这里一定要有引号 ( 单双引号均可 ), G 一定要大写

16 SELECT-FROM-WHERE SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT PName, Price, Manufacturer FROM WHERE Price > 100 特别提示 : 比较数字大小的时候不用加引号, 或者加单引号也可以, 双引号不可以 PName Price Manufacturer SingleTouch $ Canon MultiTouch $ Hitachi

17 去掉重复值 :DISTINCT SELECT FROM DISTINCT category Category Gadgets Photography Household Compare to: SELECT FROM category Category Gadgets Gadgets Photography Household

18 取头几行值 :Limit SELECT FROM Limit 3 DISTINCT category Category Gadgets Photography Household Compare to: SELECT FROM Limit 3 category Category Gadgets Gadgets Photography

19 高级筛选 :AND SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT FROM WHERE PName, Price, Manufacturer Price > 100 AND Manufacturer= Canon PName Price Manufacturer SingleTouch $ Canon

20 高级筛选 :OR SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT FROM WHERE PName, Price, Manufacturer Price > 100 OR Manufacturer= GizmoWorks 特别提示 :AND 优先级高于 OR SingleTouch $ Photography Canon MultiTouch $ Household Hitachi

21 高级筛选 :IN SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT FROM WHERE PName, Price, Manufacturer Manufacturer IN ( GizmoWorks, Canon ) SingleTouch $ Photography Canon

22 高级筛选 :NOT SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT FROM WHERE PName, Price, Manufacturer NOT Manufacturer = Hitachi SingleTouch $ Photography Canon

23 通配符 :LIKE SELECT * FROM s WHERE PName LIKE %gizmo% SingleTouch $ Photography Canon MultiTouch $ Household Hitachi 特别提示 : 与 % 能匹配 0 个字符不一样, _ 总是匹配一个字符, 不能多也不能少

24 排序 :ORDER BY ( 永远写在最后, 除非有 limit 行数 ) Powergizmo $59.99 Gadgets GizmoWorks SingleTouch $59.99 Gadgets GizmoWorks MultiTouch $79.99 Gadgets GizmoWorks SELECT pname, price, manufacturer FROM WHERE category= Gadgets AND price > 50 ORDER BY price, pname Ties are broken by the second attribute on the ORDER BY list, etc. 特别提示 :Ordering is ascending( 升序 ), unless you specify the DESC keyword.

25 练习 : Table SingleTouch $ Photography Canon MultiTouch $ Household Hitachi SELECT DISTINCT category FROM ORDER BY category? SELECT Category FROM ORDER BY PName? SELECT DISTINCT category FROM ORDER BY PName?

26 Contact Us WeChat: CareerPass 或搜 北美职通卡 Call: Website : Address: 200 Lincoln Street 200# Boston, MA 扫面下方二维码, 关注北美职通卡公众账号