Create the data

Add data to the table you just defined by using the following statement

INSERT INTO `my_first_db`.`user` (`id`.`username`.`password`.`ct`) VALUES ('1'.'hq'.'11111'.'the 2018-12-12 12:12:12');
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  • The keyword INSERT INTO indicates the insertion

  • My_first_db. user represents the name of the database and the name of the table, for example in Excel and sheet, specifying the target for data insertion

  • What is left is the specific insert data.

  • (`id`, `username`, `password`, `ct`) VALUES (‘1’, ‘hq’, ‘11111’, ‘2018-12-12 12:12:12’); The keyword VALUES in the middle divides the sentence into two paragraphs. The first paragraph is a list of field names and the second paragraph is the value of the field

The instance

INSERT INTO `my_first_db`.`user` (`id`.`username`.`password`.`ct`) VALUES ('1'.'son dragon'.'222222'.'the 2018-11-21 19:12:12');
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CP this statement to mysql Workbench, execute it, and see what happens

The result is as follows

17:04:54	INSERT INTO `my_first_db`.`user` (`id`, `username`, `password`, `ct`) VALUES ('1'.'son dragon'.'222222'.'the 2018-11-21 19:12:12')	Error Code: 1062. Duplicate entry '1' for key 'PRIMARY'0.000 SECCopy the code

Analyze the above errors

Duplicate entry ‘1’ for key ‘PRIMARY’ 0.000 SEC Error Code: 1062. Duplicate entry ‘1’ for key ‘PRIMARY’ 0.000 SEC Error Code: 1062 is not useful to us. Duplicate entry ‘1’ for key ‘PRIMARY’ 0.000 SEC

Duplicate keyword, ‘for key ‘PRIMARY” Duplicate key, so let’s change 1 to 2 and try again

Modified SQL

INSERT INTO `my_first_db`.`user` (`id`.`username`.`password`.`ct`) VALUES ('2'.'son dragon'.'222222'.'the 2018-11-21 19:12:12');
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The following information is displayed:

17:09:22	INSERT INTO `my_first_db`.`user` (`id`, `username`, `password`, `ct`) VALUES ('2'.'son dragon'.'222222'.'the 2018-11-21 19:12:12') 1 Row (s) affected 0.016 SECCopy the code

1 row(s) affected; SQL > alter table affected

Through the following Sql statement

select * from my_first_db.user
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But the following information is returned:

17:11:15	select * from user LIMIT 0, 1000	Error Code: 1046. No database selected Select the default DB to be used by double-clicking its name in the SCHEMAS list inThe sidebar. 0.000 SECCopy the code

We did not specify the default data, that is, we specified to query the user table in that database

You specify that the execution is the same as the insert statement,

Statement after adding database name:

select * from my_first_db.user
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Returns the result

'1'.'hq'.'11111'.'the 2018-12-12 12:12:12'
'2'.'son dragon'.'222222'.'the 2018-11-21 19:12:12'
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Insert, applause

Alternatively, if we’re lazy and don’t want to write my_first_db, we can execute the default database: Select the default DB to be used by double-clicking its name in the SCHEMAS list in the sidebar

Let’s do the following:

Double-click the database name to turn black to indicate that the database is the default database

Try downloading SQL without writing the database name

select * from user
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You can also return data

’17:21:49 SELECT * from user LIMIT 0, 1000 2 row(s) returned 0.000 SEC / 0.000 SEC’

What if we want to change my password, using the update statement

Modify the data

SQL

We’d like to change your password

update user set password = zlw1314 where id = 1
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Update,user is the name of the table, set, password is the value to be changed, equal is the value to be changed, and WHERE is the password to be changed only for the user whose ID is 1.