MySQLi Articles

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How can a query multiply 2 cells for each row in MySQL?

George John
George John
Updated on 30-Jul-2019 248 Views

You can use multiplication operator (*) between two cells. The syntax is as followsSELECT yourColumnName1, yourColumnName2, yourColumnName1*yourColumnName2 as ‘anyVariableName’ from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table MultiplicationDemo    -> (    -> FirstPrice int,    -> SecondPrice int    -> ); Query OK, 0 rows affected (0.63 sec)Now you can display all records from the table using insert command. The query is as followsmysql> insert into MultiplicationDemo values(10, 2); Query OK, 1 row affected (0.17 sec) mysql> insert into MultiplicationDemo values(4, 2); Query OK, ...

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Limit length of longtext field in MySQL SELECT results?

Ankith Reddy
Ankith Reddy
Updated on 30-Jul-2019 1K+ Views

You can use SUBSTRING() from MySQL to limit length of strings. The syntax is as followsSELECT SUBSTRING(yourColumnName, 1, yourIntegerValueToGetTheCharacters) as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table limitLengthOfLongTextDemo -> ( -> sentence LONGTEXT -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The query is as followsmysql> insert into limitLengthOfLongTextDemo values('This is the introduction to MySQL'); Query OK, 1 row affected (0.17 sec) mysql> insert into ...

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Solve ERROR 1396 (HY000): Operation DROP USER failed for 'user'@'localhost' in MySql?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 3K+ Views

This error occurs when you drop a user with localhost while you have created a user with ‘%’.Let us create a user with ‘%’ and drop the user as a localhost. The syntax is as followsCREATE USER 'yourUserName'@'%' IDENTIFIED BY 'yourPassword';Let us create a user using the above syntax. The query to create a user is as followsmysql> CREATE USER 'Jack'@'%' IDENTIFIED BY '1234'; Query OK, 0 rows affected (0.26 sec)Check user is created successfully or notmysql> select user, host from MySQL.user;The following is the output+------------------+-----------+ | user             | host      | +------------------+-----------+ ...

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How to set sql_mode permanently in MySQL?

George John
George John
Updated on 30-Jul-2019 1K+ Views

If you are using Windows Operating System, check your directory my.cnf or my.ini file.mysql> select @@datadir;The following is the output+---------------------------------------------+ | @@datadir | +---------------------------------------------+ | C:\ProgramData\MySQL\MySQL Server 8.0\Data\ | +---------------------------------------------+ 1 row in set (0.00 sec)Reach the above location ‘C:\ProgramData\MySQL\MySQL Server 8.0\Data\”. The screenshot is as follows for my.cnf fileOpen the my.cnf file and write the sql_mode="TRADITIONAL". The syntax is as followssql_mode="TRADITIONAL".After that start your server once again.

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How to select yesterday's date in MySQL?

Ankith Reddy
Ankith Reddy
Updated on 30-Jul-2019 720 Views

To select yesterday’s date, use the subdate() function from MySQL. The syntax is as followsselect subdate(yourDatetimeColumnName) as anyVariableName from yourTableName;To understand the above syntax, let us create a tablemysql> create table YesterdayDateDemo -> ( -> VisitedDateTime datetime -> ); Query OK, 0 rows affected (0.59 sec)Let us now insert date in the table using insert command. The query is as followsmysql> insert into YesterdayDateDemo values(now()); Query OK, 1 row affected (0.15 sec) mysql> insert into YesterdayDateDemo values('2012-12-26 13:24:35'); Query OK, 1 row affected (0.17 sec) mysql> insert into YesterdayDateDemo values('2013-10-22 12:20:32'); Query OK, 1 row affected (0.16 sec)Let ...

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Create a procedure in MySQL with parameters?

Chandu yadav
Chandu yadav
Updated on 30-Jul-2019 4K+ Views

You can create a parameter using IN and OUT. IN is used to take input parameter and OUT can be used for output.The syntax is as followsDELIMITER // CREATE PROCEDURE yourProcedureName(IN yourParameterName dataType, OUT yourParameterName dataType ) BEGIN yourStatement1; yourStatement2; . . N END; // DELIMITER ;First, we will create a table. The query to create a table is as followsmysql> create table SumOfAll -> ( -> Amount int -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command. The query ...

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What is the data type for unix_timestamp in MySQL?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 2K+ Views

The best data type for unix_timestamp in MySQL is integer. The integer data type is as followsint(11);The integer data type is useful for condition checking like ( > , create table UnixTime -> ( -> DueTime datetime -> ); Query OK, 0 rows affected (0.55 sec)Insert records in the form of date using insert command. The query is as followsmysql> insert into UnixTime values(now()); Query OK, 1 row affected (0.15 sec) mysql> insert into UnixTime values('2010-10-14'); Query OK, 1 row affected (0.15 sec) mysql> insert into UnixTime values('2020-09-24'); Query ...

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How to add column values in MySQL without using aggregate function?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 447 Views

You can add column values without using aggregate function like sum(). For that, the syntax is as follows −SELECT *, (yourColumnName1+yourColumnName2+yourColumnName3, ....N) as anyVariableName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table AddingColumnDemo    -> (    -> StudentId int,    -> StudentName varchar(20),    -> MathMarks int,    -> PhysicsMarks int,    -> ChemistryMarks int    -> ); Query OK, 0 rows affected (0.82 sec)Insert records in the table using insert command. The query is as follows −mysql> insert into AddingColumnDemo values(1, 'John', 35, ...

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How to output MySQL query results in CSV format and display it on the screen, not a file?

George John
George John
Updated on 30-Jul-2019 724 Views

To get the output MySQL query result in CSV format, use concat(). The syntax is as follows −mysql> select concat(StudentId, ', ', StudentName, ', ', StudentAge) as CSVFormat from CSVFormatOutputs;To understand the above syntax, let us create a table. The query to create a table is as follows−mysql> create table CSVFormatOutputs    -> (    -> StudentId int not null auto_increment,    -> StudentName varchar(20),    -> StudentAge int,    -> PRIMARY KEY(StudentId)    -> ); Query OK, 0 rows affected (1.15 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into CSVFormatOutputs(StudentName, ...

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Changing year in MySQL date?

Arjun Thakur
Arjun Thakur
Updated on 30-Jul-2019 5K+ Views

To change the year in MySQL date, you need to use DATE_FORMAT() function with UPDATE command. The syntax is as follows.UPDATE yourTableName SET yourDateColumnName = DATE_FORMAT(yourDateColumnName ,'yourYearValue-%m-%d');To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table ChangeYear    -> (    -> id int not null auto_increment,    -> ArrivalTime date,    -> PRIMARY KEY(id)    -> ); Query OK, 0 rows affected (0.83 sec)Insert some records in the table using insert command −mysql> insert into ChangeYear(ArrivalTime) values(date_add(now(), interval -2 year)); Query OK, 1 row affected, 1 warning ...

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