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What are the basic database operations?

Basic database operations include:

1 Basic operations on databases

SHOW DATABASES;//Query database SHOW CREATE DATABASE score; //Query database structure CREATE DATABASE score DEFAULT CHARSET utf8; //Create database USE score; //Use score database DROP DATABASE score; //Delete database

2 Operations on tables

SHOW TABLES; //Display tables in the database CREATE TABLE score(sno INT PRIMARY KEY AUTO_INCREMENT,course VARCHAR(20),sscore SMALLINT); //Create table SHOW CREATE TABLE score; //Display the construct table statement DESC score; //Display table knot ALTER TABLE scoreADD startTime DATE NOT NULL; //add field ALTER TABLE scoreDROP startTime; //delete fields ALTER TABLE scoreMODIFY course VARCHAR(50); //modify field type ALTER TABLE scoreCHANGE startTime endTime DATE; //Change field name DROP TABLE score; //Delete table

3 Management data

INSERT INTO score(course,sscore)VALUES ('language ', 80); //add data UPDATE scoreSET sscore=90WHERE sno=1; //Delete from scoreWHERE sno=1; //Delete data

4 Inquiry data

SELECT * FROM score; //Query all field data

Select distinct field from table name where condition

Logical conditions: and or

Comparison conditions:

=, , between value1 and value2

Judgment null:

1) null: is null

2)Judge empty string: ="" / ""

Fuzzy condition: like

%: Replace arbitrary length characters

_: Replace a single character

pagination query, limit start row, query rows

Sort: order by field asc/desc

asc: ascending

desc: descending order

Group: group by field

5 Code queries in databases

SHOW VARIABLES LIKE 'character%';Variable_name Valuecharacter_set_client utf8character_set_connection utf8character_set_database utf8character_set_filesystem binarycharacter_set_results utf8character_set_server utf8character_set_system utf8character_sets_dir C:\\Program Files\\MySQL\\MySQL Server 5.7\\share\\charsets\\

If garbled characters appear in the query process, they can be solved by setting the corresponding character encoding.

For example, when cmd client queries, there may be Chinese in the database, the code set by database character_set_client is utf8, and cmd interpretation is interpreted by gbk. So there will be garbled code, set the character_set_client code to gbk.

SET character_set_client='gbk'; Thank you for reading! About "database basic operation statement" this article is shared here, I hope the above content can be of some help to everyone, so that everyone can learn more knowledge, if you think the article is good, you can share it to let more people see it!

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