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This article mainly introduces the operation examples of line records in MySQL, which is very detailed and has a certain reference value. Friends who are interested must finish reading it!

In Mysql management software, you can manipulate data through the dml language in sql statements, including

1. Use INSERT to insert data.

2. Update the data by UPDATE

3. Use DELETE to delete data.

4. Use SELECT to query data and

Insert data INSERT

. Insert complete data (sequential insert) syntax 1: INSERT INTO table name (field 1, field 2, field 3 … Field n) VALUES (value 1, value 2, value 3... Value n); # specify the field to insert the data, and the inserted value should match your previous field. Syntax 2: INSERT INTO table name VALUES (value 1, value 2, value 3... Value n); # if no field is specified, insert data 2. 0 according to the default fields. Specify field insertion data syntax: INSERT INTO table name (field 1, field 2, field 3...) VALUES (value 1, value 2, value 3...) ; 3. Insert multiple records syntax: # insert multiple records to separate the INSERT INTO table name VALUES with commas (value 1, value 2, value 3 … Value n), (value 1, value 2, value 3... Value n), (value 1, value 2, value 3... Value n); 4. Insert query result syntax: INSERT INTO table name (field 1, field 2, field 3... Field n) SELECT (Fields 1, 2, 3... Field n) FROM Table 2 WHERE... Insert the results queried from Table 2 into our table, but make sure that the queried data corresponds to the fields we specified earlier

Update data: UPDATE

Syntax: UPDATE table name SET field 1 = value 1, # Note syntax, multiple values can be modified at the same time, fields 2 = value 2 are separated by commas, which data is changed by WHERE CONDITION; #, and data that meets the criteria is located through where conditions example: UPDATE mysql.user SET password=password ('123') where user='root' and host='localhost' # this sentence modifies the data of the password field of the record whose user field is' root' and host field is' localhost''in the user table in the myslq library, and changes the data in the passord field to password ('123'). The method of password () is used to encrypt the password provided by mysql. Navigate to a record and change something in that record

Delete data DELETE

Syntax: DELETE FROM table name WHERE CONITION; # delete some records that meet the criteria DELETE FROM table name If you do not add the where condition, it means to delete all the contents of the table, but clear all the contents. Generally, we use truncate to set id to zero. Delete cannot set id to zero. When inserting data, it will continue to increase the number of id recorded in the previous data. Example: DELETE FROM mysql.user WHERE password='123' Exercise: update the MySQL root user password to mysql123 to delete all users except locally logged in root users

Query data SELECT (most frequently used)

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