MySQL Tutorial chapter 5th inserting updates and deleting data

Chapter 5th inserting updates and deleting data

Connect to SCHOOLDB using the SQL Manager management tool. Because the primary key is set for three tables, the primary key cannot be weighed in the following exercise.

Inserting data

1. Exercise: Insert data for all fields of a table

Insert data for all fields in a table without specifying a column

where into can save

INSERT into tstudent values (' 00008 ', ' Baek ampoule ', ' Male ', ' 132302197604044565 ', ' 19760404 ',

' [email protected] ', ' JAVA ', ' 20120803 ')

Insert Tstudent values (' 00009 ', ' Bai Aming ', ' Male ', ' 132302197604044565 ', ' 19760404 ',

' [email protected] ', ' JAVA ', ' 20120803 ')

SELECT * from ' tstudent '

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2. Exercise: Insert a field for the specified column of a table

The order of the columns can be different from the order of the columns in the table

Insert Tstudent (Sname,studentid,sex) VALUES (' Liu Qingming ', ' 00010 ', ' Male ')

SELECT * from ' tstudent '

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3. Practice: Inserting multiple records at the same time

Insert Tstudent (Sname,studentid,sex) VALUES (' Kim Jong-un ', ' 00011 ', ' Male '), (' Kim Jong-il ', ' 00012 ', ' Male ')

4. Exercise: Inserting query results into a new table

Create a new table

CREATE TABLE SP

(

StudentID varchar (15),

Sname varchar (10),

Sex char (1)

)

The following command inserts a tstudent student from the table into a new table

Insert SP (studentid,sname,sex) Select Studentid,sname,sex from ' tstudent ' where sname like ' Gold% '

SELECT * FROM SP

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Update data

5. Exercise: Update data

Change the name and gender of a student who learns to be 00010

Update ' tstudent ' Set sname= ' Liu Minghui ', sex= ' female ' where studentid= ' 00010 '

View changes after a change

SELECT * from ' tstudent ' where studentid= ' 00010 '

Add 10 points to the computer network score named Han Ligang

View Han Ligang's computer network now scores

Update ' Tscore ' set mark=mark+10 where ' Tscore '. ' StudentID ' =

(select StudentID from ' tstudent ' where sname= ' Han Li just ') and ' tscore '. ' Subjectid ' =

(select Subjectid from ' Tsubject ' where subjectname= ' computer network ')

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Update ' Tscore ' set mark=mark+10 where ' Tscore '. ' StudentID ' =

(select StudentID from ' tstudent ' where sname= ' Han Li just ') and ' tscore '. ' Subjectid ' =

(select Subjectid from ' Tsubject ' where subjectname= ' computer network ')

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Deleting records

6. Exercise: Delete a record

Delete student name is Liu Minghui student record

Delete from ' tstudent ' where sname= ' Liu Minghui '

Delete Han Ligang's scores

Delete from ' Tscore ' where ' tscore '. ' StudentID ' = (select StudentID from ' Tstudent ' where

Sname= ' Han Li just ')

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