To change the file extension in the text column, you can use UPDATE command along with REPLACE() function. Let’s say we have some columns with extensions and we need to replace all of them. For that, let us first create a table with the extension columns set as text type:mysql create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    ProgramExtension1 text,    ProgramExtension2 text,    ImageExtension text ); Query OK, 0 rows affected (0.52 sec)Following is the query to insert records in the table using insert command:mysql> insert into DemoTable(ProgramExtension1, ProgramExtension2, ImageExtension)values('.java', '.c', '.jpeg'); Query OK, ... Read More

You can use aggregate function COUNT() from MySQL to count horizontal values on a database. Let us first create a table −mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    FirstValue int,    SecondValue int,    ThirdValue int,    FourthValue int ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue, FourthValue) values(-18, 45, 0, 155); Query OK,  1 row affected (0.22 sec) mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue, FourthValue) values(0, 235, null, 15); Query OK,  1 row affected (0.20 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following ... Read More

You can use aggregate function SUM() from MySQL for this. Let us first create a table −mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Amount int ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Amount) values(400); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(Amount) values(10); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(Amount) values(50); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(Amount) values(500); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(Amount) ... Read More

Yes, we can ignore duplicate rows in COUNT using DISTINCT. Following is the syntax:select count(distinct yourColumnName) from yourTableName;In MySQL, COUNT() will display the number of rows. DISTINCT is used to ignore duplicate rows and get the count of only unique rows.Let us first create a table:mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    FirstName varchar(10) ); Query OK, 0 rows affected (0.47 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(FirstName) values('Larry'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(FirstName) values('John'); Query OK, ... Read More

You can use DATE() function from MySQL for this. Let us first create a table −mysql> create table DemoTable (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentAdmissionDate timestamp ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentAdmissionDate) values('2011-01-12 12:34:43'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(StudentAdmissionDate) values('2012-10-23 11:32:21'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(StudentAdmissionDate) values('2001-02-14 05:12:01'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(StudentAdmissionDate) values('2018-12-31 15:10:04'); Query OK, 1 row affected (0.22 sec) mysql> ... Read More

To update a range of records in MySQL, you can use BETWEEN. Let us first create a table:mysql> create table DemoTable (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Name varchar(20),    Age int ); Query OK, 0 rows affected (0.53 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(Name, Age) values('Larry', 23); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(Name, Age) values('Sam', 24); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable(Name, Age) values('Chris', 21); Query OK, 1 row affected (0.10 sec) mysql> insert ... Read More

You can use GROUP_CONCAT() function to list all the items in a group in one record. Let us first create a table −mysql> create table DemoTable (    ProductId int,    ProductName varchar(40),    ProductCategory varchar(40) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Product-1', '1Product'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(101, 'Product-2', '2Product'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(100, 'Product-1', '3Product'); Query OK, 1 row affected (0.14 sec)Following is the query to display all ... Read More

The most efficient want to check the presence of a row, use the count():select count(1) from yourTableName where yourCondition;Let us first create a table:mysql> create table DemoTable (    Id int,    FirstName varchar(20) ); Query OK, 0 rows affected (0.73 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable values(100, 'Larry'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(110, 'Sam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(120, 'Mike'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(130, 'Carol'); Query ... Read More

To turn ON the general log, you need to use SET command. Following is the syntax −set global general_log=ON;Let us check the general log status with the help of SHOW command −mysql> SHOW variables like '%general_log%';This will produce the following output −+------------------+---------------------+ | Variable_name | Value | +------------------+---------------------+ | general_log | OFF | | general_log_file | DESKTOP-QN2RB3H.log | +------------------+---------------------+ 2 rows in set ... Read More

First of all, you need to check the host. The host can be ‘localhost’ or ‘%’. Check the existence of user accounts with host −mysql> select user, host from MySQL.user;This will produce the following output −+------------------+-----------+ | user             | host      | +------------------+-----------+ | Bob              | % | | User2            | % | | mysql.infoschema | % | ... Read More