MySQL Articles

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MySQL server version for the right syntax to use near 'OPTION SQL_SELECT_LIMIT=10'?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 854 Views

You can use SET command, but SET OPTIOn deprecated. Therefore, use SET SQL_SELECT_LIMIT.The syntax is as follows −SET SQL_SELECT_LIMIT=yourIntegerValue;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table MySQLSelectDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY    -> ); Query OK, 0 rows affected (0.99 sec)Insert some records in the table using insert command. The query is as follows −mysql> INSERT INTO MySQLSelectDemo VALUES(), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), (), ...

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Is it possible to have View and table with the same name in MySQL?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 1K+ Views

No, you cannot give the same name for view and table in MySQL.Let us first create a demo table −mysql> create table view_Table_Demo    -> (    -> Id int,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into view_Table_Demo values(100, 'Larry'); Query OK, 1 row affected (0.17 sec) mysql> insert into view_Table_Demo values(101, 'Mike'); Query OK, 1 row affected (0.20 sec) mysql> insert into view_Table_Demo values(102, 'Sam'); Query OK, 1 row affected (0.14 sec)Display all ...

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Does MySQL eliminate common subexpressions between SELECT and HAVING/GROUP BY clause? How to test it?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 152 Views

To test, use the sleep() function.Case 1 −The syntax is as follows −SELECT yourColumnName+sleep(yourIntegerValue) FROM yourTableName GROUP BY yourColumnName+sleep(yourIntegerValue);;Case 2 − You can use another syntax which is as follows −SELECT yourColumnName+sleep(yourIntegerValue) As anyAliasName FROM yourTableName GROUP BY yourAliasName;To understand the above syntaxes, let us create a table. The query to create a table is as follows −mysql> create table sleepDemo    -> (    -> value int    -> ); Query OK, 0 rows affected (1.25 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into sleepDemo values(40); Query OK, 1 row ...

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MySQL select dates in 30-day range?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 2K+ Views

To select dates in 30-day range, you can use arithmetic operation - with interval.The syntax is as follows −select *from yourTableName where yourDateColumnName > NOW() - INTERVAL 30 DAY and yourDateColumnName < NOW() + INTERVAL 30 DAY;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectDatesDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> ArrivalDate datetime    -> ); Query OK, 0 rows affected (0.77 sec)Now you can insert some records in the table using insert command. The query is as ...

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How to remove hyphens using MySQL UPDATE?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 998 Views

To remove hyphens using MySQL update, you can use replace() function. The syntax is as follows −update yourTableName    set yourColumnName=replace(yourColumnName, '-', '' );To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table removeHyphensDemo    -> (    -> userId varchar(100)    -> ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into removeHyphensDemo values('John-123-456'); Query OK, 1 row affected (0.22 sec) mysql> insert into removeHyphensDemo values('Carol-9999-7777-66555'); Query OK, 1 row affected (0.19 sec) ...

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Count top 10 most occurring values in a column in MySQL?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 1K+ Views

To count the top 10 most occurring values in a column in MySQL, The syntax is as follows −SELECT yourColumnName, count(*)    FROM yourTableName    GROUP BY yourColumnName    ORDER BY count(*) DESC    LIMIT 10;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table countTop10Demo    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.74 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into countTop10Demo values(10); Query OK, 1 row affected (0.12 sec) ...

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What is the PHP equivalent of MySQL's UNHEX()?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 728 Views

You can use hex2bin() function since it is the PHP equivalent of MySQL's UNHEX().The syntax is as follows −$anyVariableName = hex2bin("yourHexadecimalValue");To understand the above syntax, let us implement the above syntax in PHP. The PHP code is as follows −$myFirstValue = hex2bin("7777772E4D7953514C4578616D706C652E636F6D"); var_dump($myFirstValue); $mySecondValue=hex2bin("416476616E6365644A617661576974684672616D65776F726B"); echo(''); var_dump($mySecondValue);The snapshot of PHP code is as follows −Here is the snapshot of The output −Here is the MySQL UNHEX() −Case 1 − The query is as follows −mysql> SELECT UNHEX("7777772E4D7953514C4578616D706C652E636F6D");The following is The output −+---------------------------------------------------+ | UNHEX("7777772E4D7953514C4578616D706C652E636F6D") | +---------------------------------------------------+ | www.MySQLExample.com ...

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MySQL select order by acts like a string (not a number)?

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 267 Views

You can use the following syntax if your column has varchar data type −select yourColumnName FROM yourTableName ORDER BY yourColumnName +0 DESC;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectOrderdemo    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Name varchar(100),    -> RankNumber varchar(100)    -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into selectOrderdemo(Name, RankNumber) values('Larry', -100); Query OK, 1 row affected (0.23 ...

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MySQL where column = 'x, y, z'?

Samual Sam
Samual Sam
Updated on 30-Jul-2019 464 Views

You can use IN operator for this.The syntax is as follows −SELECT *FROM yourTableName WHERE yourColumnName IN(‘yourValue1’, ‘yourValue2’, ‘yourValue3’, ...........N);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table InOperatorDemo    -> (    -> ClientId int    -> ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into InOperatorDemo values(101); Query OK, 1 row affected (0.19 sec) mysql> insert into InOperatorDemo values(110); Query OK, 1 row affected (0.11 sec) mysql> insert into InOperatorDemo ...

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MySQL query to skip the duplicate and select only one from the duplicated values

karthikeya Boyini
karthikeya Boyini
Updated on 30-Jul-2019 1K+ Views

The syntax is as follows to skip the duplicate value and select only one from the duplicated values −select min(yourColumnName1), yourColumnName2 from yourTableName group by yourColumnName2;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table doNotSelectDuplicateValuesDemo    -> (    -> User_Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> User_Name varchar(20)    -> ); Query OK, 0 rows affected (0.78 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into doNotSelectDuplicateValuesDemo(User_Name) values('John'); Query OK, 1 row affected ...

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