Found 6702 Articles for Database

Why the G modifier in SELECT * FROM table_nameG?

George John
Updated on 30-Jul-2019 22:30:24

124 Views

The \G modifier gets the result in vertical order. If you use \g modifier, then it won’t affect the result. The \g works likesemi-colon.Let us first create a table. The query to create a table is as follows:mysql> create table DemoOfVertical    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(20),    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (3.40 sec)Now you can insert some records in the table using insert command. The query is as follows:mysql> insert into DemoOfVertical(Name) values('Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into ... Read More

Get Last Entry in a MySQL table?

Chandu yadav
Updated on 30-Jul-2019 22:30:24

1K+ Views

You can get the last entry in a MySQL table using ORDER BY. The first approach is as follows:Case 1: Using DESC LIMITSELECT * FROM yourTableName ORDER BY yourColumnName DESC LIMIT 1;The second approach is as follows:Case 2: Using MAX()SET @anyVariableName = (SELECT MAX(yourColumnName) FROM yourTableName); SELECT *FROM yourtableName WHERE yourColumnName = @anyVariableName;Now to understand both the approaches, let us create a table. The query to create a table is as follows:mysql> create table lastEntryDemo    -> (    -> Id int NOt NULL AUTO_INCREMENT,    -> Name varchar(30),    -> Age int,    -> PRIMARY KEY(Id)    -> ); ... Read More

How to remove double or more spaces from a string in MySQL?

Ankith Reddy
Updated on 30-Jul-2019 22:30:24

701 Views

You can create a function to remove double or more spaces from a string. The syntax is as follows:DELIMITER // create function yourFunctionName(paramter1, ...N) returns datatype; begin //your statement. end; // DELIMITER ;Here’s how to create a function:mysql> delimiter // mysql> create function function_DeleteSpaces(value varchar(200)) returns varchar(200)    -> begin    -> set value = trim(value);    -> while instr(value, ' ') > 0 do    -> set value = replace(value, ' ', ' ');    -> end while;    -> return value;    -> END;    -> // Query OK, 0 rows affected (0.20 sec) mysql> delimiter ;Now you ... Read More

How can I update the boolean values in MySQL?

Arjun Thakur
Updated on 30-Jun-2020 07:14:49

12K+ Views

You can update boolean value using UPDATE command. If you use the BOOLEAN data type, MySQL internally convert it into tinyint(1). It can takes true or false literal in which true indicates 1 to tinyint(1) and false indicates 0 to tinyint(1).The syntax is as follows −UPDATE yourTableName SET yourColumnName = yourValue WHERE yourCondition;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table UpdateBooleans    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> isSuccessful BOOLEAN,    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows ... Read More

MySQL order by string with numbers?

George John
Updated on 30-Jun-2020 07:20:00

5K+ Views

To MySQL order string with numbers, the following is the syntax, wherein we have used ORDER BY, SUBSTR() and CAST() −SELECT *FROM yourTableName ORDER BY SUBSTR(yourColumnName FROM 1 FOR 2), CAST(SUBSTR(yourColumnName FROM 2) AS UNSIGNED);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table OrderByStringWithNumbers    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Words varchar(10),    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert ... Read More

How to map keys to values for an individual field in a MySQL select query?

Chandu yadav
Updated on 30-Jun-2020 07:22:47

2K+ Views

You can use CASE statement in MySQL to map keys to values for an individual field in select query. The syntax is as follows −SELECT yourColumnName1, yourColumnName2, yourColumnName3, .........N (    CASE WHEN yourColumnName = 1 THEN 'ENABLED'    ELSE 'DISABLED'    END ) AS anyVariableName FROM yourTableName;You can use IF() function also for the same purpose. The syntax is as follows −SELECT yourColumnName1, yourColumnName2, yourColumnName3, .........N ,IF(yourColumnName, 'ENABLED', 'DISABLED') 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 MapKeys    -> (   ... Read More

MySQL get hash value for each row?

Ankith Reddy
Updated on 30-Jun-2020 07:24:41

2K+ Views

Get hash value of each row using MD5() function from MySQL. The syntax is as follows −SELECT MD5(CONCAT(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 getHashValueForEachRow    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(20),    -> Age int,    -> Marks int,    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (1.25 sec)Insert records in the table using insert command. The query is as follows −mysql> insert into getHashValueForEachRow(Name, Age, ... Read More

Convert dd/mm/yyyy string to Unix timestamp in MySQL?

Arjun Thakur
Updated on 30-Jun-2020 07:25:47

388 Views

Convert dd/mm/yyyy string to Unix timestamp with the help of UNIX_TIMESTAMP(). The syntax is as follows −SELECT UNIX_TIMESTAMP(STR_TO_DATE(yourColumnName, '%d/%m/%Y')) 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 ConvertddmmyyyyInUnixTimeStamp    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Created_at varchar(30),    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into ConvertddmmyyyyInUnixTimeStamp(Created_at) values('10/11/2012'); Query OK, 1 row affected (0.21 sec) mysql> ... Read More

MySQL LIMIT to select a single row

George John
Updated on 30-Jun-2020 07:28:32

403 Views

To select a single row in MySQL, you can use LIMIT. At first, let us create a table. The query to create a table is as follows −mysql> create table selectWithPrimaryKey    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(20),    -> Age int,    -> Marks int,    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into selectWithPrimaryKey(Name, Age, Marks) values('Larry', 24, 98); Query OK, 1 row affected (0.15 sec) mysql> insert into ... Read More

Change date format (in DB or output) to dd/mm/yyyy in PHP MySQL?

Chandu yadav
Updated on 30-Jun-2020 07:30:05

2K+ Views

You can change the date format in PHP using date() fucntion. The syntax is as follows −date(d/m/Y, yourDateTimeVariable);In PHP, convert string to date using strtodate(). Here is the PHP code used to format the datetime −$LogintDate = strtotime('2019-01-12'); echo date('d/m/Y', $LogintDate);The snapshot of code is as follows −The following is the output −12/01/2019You can achieve in MySQL with the help of date_format() function. The syntax is as follows −SELECT DATE_FORMAT(yourColumnName, ’%d/%m/%Y’) as anyVariableName FROM yourTableName;To understand the above syntax, let us create a table −mysql> create table Date_FormatDemo    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> ... Read More

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