{"id":6095,"date":"2021-01-29T05:34:05","date_gmt":"2021-01-29T05:34:05","guid":{"rendered":"https:\/\/prwatech.in\/blog\/?p=6095"},"modified":"2024-03-27T08:02:27","modified_gmt":"2024-03-27T08:02:27","slug":"mysql-basic-commands","status":"publish","type":"post","link":"https:\/\/prwatech.in\/blog\/mysql\/mysql-basic-commands\/mysql-basic-commands\/","title":{"rendered":"MYSQL BASIC COMMANDS"},"content":{"rendered":"\r\n

MYSQL<\/a> BASIC<\/a> COMMANDS<\/h2>\r\n

 <\/p>\r\n\r\n\r\n\r\n

Create a database<\/em><\/p>\r\n\r\n\r\n\r\n

create database Prwatech;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

List all database on the server<\/em><\/p>\r\n\r\n\r\n\r\n

show databases;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

Switch to a database<\/em><\/p>\r\n\r\n\r\n\r\n

use prwatech;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

Create a table in the database<\/em><\/p>\r\n\r\n\r\n\r\n

CREATE\u00a0TABLE\u00a0Persons (
\u00a0\u00a0\u00a0 PersonID int,
\u00a0\u00a0\u00a0 LastName varchar(255),
\u00a0\u00a0\u00a0 FirstName varchar(255),
\u00a0\u00a0\u00a0 Address varchar(255),
\u00a0\u00a0\u00a0 City varchar(255)
);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To see all the tables in the database<\/em><\/h3>\r\n\r\n\r\n\r\n

show tables;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To\u00a0see a table\u00a0<\/strong>field format<\/em><\/p>\r\n\r\n\r\n\r\n

describe persons;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To\u00a0delete a database<\/strong><\/em><\/p>\r\n\r\n\r\n\r\n

drop database sys;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To\u00a0delete a table<\/strong>\u00a0in the database<\/em><\/p>\r\n\r\n\r\n\r\n

drop table persons;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To see the\u00a0column information<\/strong>\u00a0in the table of the database<\/em><\/p>\r\n\r\n\r\n\r\n

show columns from Institute;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

Inserting information to a table in the database;<\/em><\/p>\r\n\r\n\r\n\r\n

INSERT INTO Institute (Course, Duration, Fees, Name, Country, Postalcode)<\/strong><\/p>\r\n\r\n\r\n\r\n

VALUES (\u2018Big Data\u2019, \u20186 months\u2019, \u201830000\u2019, \u2018George\u2019, \u2018India\u2019,\u2019560039\u2032);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

Adding a column into a table<\/em><\/p>\r\n\r\n\r\n\r\n

ALTER TABLE Institute<\/strong><\/p>\r\n\r\n\r\n\r\n

-> ADD Email varchar(255);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

To delete a column in a table<\/em><\/p>\r\n\r\n\r\n\r\n

ALTER TABLE Institute<\/strong><\/p>\r\n\r\n\r\n\r\n

-> DROP COLUMN Email;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

The following SQL ensures that the \u201cID\u201d, \u201cLastName\u201d, and \u201cFirstName\u201d columns will NOT accept NULL values when the \u201cPersons\u201d table is created:<\/em><\/p>\r\n\r\n\r\n\r\n

The\u00a0<\/em>NOT NULL<\/strong>\u00a0constraint enforces a column to\u00a0NOT<\/strong>\u00a0accept\u00a0NULL<\/strong>\u00a0values.<\/em><\/p>\r\n\r\n\r\n\r\n

CREATE\u00a0TABLE\u00a0Persons (
\u00a0\u00a0\u00a0 ID int\u00a0NOT\u00a0NULL,
\u00a0\u00a0\u00a0\u00a0LastName varchar(255)\u00a0NOT\u00a0NULL,
\u00a0\u00a0\u00a0 FirstName varchar(255)\u00a0NOT\u00a0NULL,
\u00a0\u00a0\u00a0 Age int
);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

show columns from persons;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

SQL UNIQUE Constraint<\/strong><\/p>\r\n\r\n\r\n\r\n

The UNIQUE constraint ensures that all values in a column are different.<\/em><\/p>\r\n\r\n\r\n\r\n

 <\/p>\r\n\r\n\r\n\r\n

ALTER TABLE Persons<\/strong><\/p>\r\n\r\n\r\n\r\n

-> ADD CONSTRAINT UC_Person UNIQUE (ID,LastName);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

SQL Check on ALTER TABLE<\/strong><\/p>\r\n\r\n\r\n\r\n

To create a\u00a0CHECK<\/strong>\u00a0constraint on the \u201cAge\u201d column when the table is already created, use the following SQL:<\/em><\/p>\r\n\r\n\r\n\r\n

 <\/p>\r\n\r\n\r\n\r\n

ALTER TABLE Persons<\/strong><\/p>\r\n\r\n\r\n\r\n

-> ADD CHECK (Age>=33);<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

SQL\u00a0Default\u00a0<\/strong>on ALTER TABLE<\/p>\r\n\r\n\r\n\r\n

To create a\u00a0DEFAULT<\/strong>\u00a0constraint on the \u201cCity\u201d column when the table is already created, use the following SQL:<\/em><\/p>\r\n\r\n\r\n\r\n

ALTER TABLE training<\/strong><\/p>\r\n\r\n\r\n\r\n

-> ALTER CITY SET DEFAULT \u2018Bangalore\u2019;<\/strong><\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

SQL CREATE INDEX STATEMENT<\/strong><\/p>\r\n\r\n\r\n\r\n

The CREATE INDEX statement is used to create indexes in tables.<\/em><\/p>\r\n\r\n\r\n\r\n

 <\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n\r\n\r\n\r\n

AUTO INCREMENT Field<\/strong><\/p>\r\n\r\n\r\n\r\n

Auto-increment<\/strong>\u00a0allows a unique number to be generated automatically .<\/em><\/p>\r\n\r\n\r\n\r\n

 <\/p>\r\n\r\n\r\n\r\n

\"\"<\/figure>\r\n","protected":false},"excerpt":{"rendered":"

MYSQL BASIC COMMANDS   Create a database create database Prwatech; List all database on the server show databases; Switch to a database use prwatech; Create a table in the database CREATE\u00a0TABLE\u00a0Persons (\u00a0\u00a0\u00a0 PersonID int,\u00a0\u00a0\u00a0 LastName varchar(255),\u00a0\u00a0\u00a0 FirstName varchar(255),\u00a0\u00a0\u00a0 Address varchar(255),\u00a0\u00a0\u00a0 City varchar(255)); To see all the tables in the database show tables; To\u00a0see a table\u00a0field […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[602,1688],"tags":[],"class_list":["post-6095","post","type-post","status-publish","format-standard","hentry","category-mysql","category-mysql-basic-commands"],"acf":[],"yoast_head":"\nMySQL Basic Commands - Prwatech<\/title>\n<meta name=\"description\" content=\"Master MySQL Basic Commands - Dive deep with our expert instructors and comprehensive curriculum.\" \/>\n<meta name=\"robots\" content=\"noindex, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"MySQL Basic Commands - 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