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2025-01-18 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Database >
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Summary of T-SQL query statement
Security code: where there is a will, there is a way, burn one's bridges and sink the boat, hundred and two Qin Guan will eventually belong to Chu.
Case 6: the table is shown in the following figure
It appears in the database as:
Lab requirements:
1. Two table queries
Select student form. Name, student table 1. Telephone, student table 1. Home address
From student table, student table 1
Where student form. Student id= Student Table 1. Student id
2. Query of three tables
Select student form. Name, course schedule. Course name, transcript. Score
From student table, course schedule, grade sheet
Where student form. Student id= score sheet. Student id AND score sheet. Course ID= course schedule. Course ID
3. Merge two result sets
SELECT name, student number, class, nationality
FROM Class two
UNION
Select surname +''+ first name, student number, class, nationality
Class one of from
Order by class desc, student number asc
4. Internal connection (find the name and CNT score of the students taking the exam, telephone number)
Select s. Name, s. Phone, c.CNT
FROM student basic information form AS S INNER JOIN student grade sheet AS C
ON S. Name = C. Name
5. Left outer link (look up the names and CNT scores of the students in this class, telephone number)
Select s. Name, s. Phone, c.CNT
FROM student basic information form AS S LEFT OUTER JOIN student grade sheet AS C
ON S. Name = C. Name
6. Right outer connection (find the name and CNT of the students taking this exam, telephone number)
Select s. Name, s. Phone, c.CNT
FROM student basic information form AS S RIGHT OUTER JOIN student grade sheet AS C
ON S. Name = C. Name
7. Full connection (find out the examination status of all students)
Select s. Name, s. Phone, c.CNT
FROM student basic information form AS S FULL OUTER JOIN student grade sheet AS C
ON S. Name = C. Name
8. Self-connect (find the name of each employee's boss)
SELECT Y. Employee name, s. Employee name AS boss name
From employee information table as y inner join employee information table as s
On y. Boss ID=S. Employee ID
9. Subquery (find production quantity per quarter, percentage)
Select quarter, sum (production quantity) AS production quantity per quarter
Str ((sum (production quantity) / (select sum (production quantity) from production Table)) * 100) +'%'AS percentage
From production table
Group by quarter
Order by quarter
10. Use SELECT in the where clause to find students with course ID=1 and scores > 80
Select student form. Name
From student table
Where 80
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