DELETE statement in MySQL
Hello and
welcome everyone. In this article, we will learn about the DELETE statement in
MySQL. Let’s go.
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The MySQL
DELETE command is used to delete rows data that is not important or you want to
remove from table. You can remove more than one row at a time using DELETE
command. You can use DELETE command with WHERE clause. When large number of
rows that you want to remove then you can use DELETE command and it’s an
advantage. Before deleting rows data take a backup for deleting data, because
once you deleted row it can’t recovered.
Most
important thing is when you deleting specific rows data from the table, then
you need to use WHERE command. One thing keeps in mind if you are not used
WHERE clause, then all rows data from the table will be deleted.
Following
are the DELETE command syntax that provided by MySQL:
DELETE FROM
table_name
WHERE condition
ORDER BY column_name
LIMIT row_count;
Here is
DELETE FROM – it is a delete rows data
command in MySQL
table_name – which tables
row data you want to delete then specify the table name here.
WHERE condition – it is
optional, but if you want to specific row delete then use WHERE condition. If
the condition matches with rows then it will be deleted otherwise MySQL fetch
error.
ORDER BY column_name – rows
will delete in specific order.
LIMIT row_count – here you
can place limit on the number of rows that you want to deleted.
For
Example:
Here is
the, we will create a table for an employee in the database.
CREATE
TABLE IF NOT EXISTS employee (
e_id
int (10) PRIMARY KEY,
e_firstname
varchar (50) NOT NULL,
e_lastname
varchar (50) NOT NULL,
e_age
int (10),
e_city
varchar (250)
e_sex
char (1)
e_phnumber
int (15) NOT NULL
)
Here we
insert record in the employee table.
INSERT INTO employee (
‘e_id’, ’e_firstname’, ’e_lastname’,
’e_age’, ’e_city’, ’e_sex’,
’e_phnumber’
)
VALUES
(
1, ‘Hone’, ‘Reus’, 25, ‘San Jose’, ‘M’, ‘ +
1 555 555 1111’
),
(
2, ‘Cries’, ’Fence’, 23, ’Fresno’, ’F’, ’
+1 555 555 1111’
);
Final
Result
‘e_id’ ’e_firstname’ ’e_lastname’ ’e_age’ ’e_city’ ’e_sex’ ’e_phnumber’
1 Hone Reus 25 San Jose
M +1 555 555 1111
2 Cries Fence 23 Fresno F +1 555 555 1111
Now, I
want to delete all the rows from employee table.
DELETE FROM employee;
Then all
rows data will be deleted.
So I want
to delete first row from employee table.
DELETE FROM employee
WHERE e_id = ‘1’;
Let see
the result after executing above query.
SELECT * FROM employee;
‘e_id’ ’e_firstname’ ’e_lastname’ ’e_age’ ’e_city’ ’e_sex’ ’e_phnumber’
2 Cries Fence 23 Fresno F +1 555 555 1111
In this
article, we are learned about DELETE keyword with example. Most important thing
is when you deleting specific rows data from the table, then you need to use
WHERE command. One thing keeps in mind if you are not used WHERE clause, then
all rows data from the table will be deleted.
MongoDB with .Net Core course link => https://www.udemy.com/mongodb-with-net-core-sagar-jaybhay/
C# basic course click on: https://www.udemy.com/learn-csharp-with-sagar-jaybhay/
Web API 2- .Net Core In depth In 5 Hours
click on: https://www.udemy.com/web-api-2-net-core-in-depth-in-5-hrs-with-sagar-jaybhay/
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