Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles on Trending Technologies
Technical articles with clear explanations and examples
Rename Root @ localhost username in MySQL?
The syntax is as follows to rename Root @localhostUPDATE MySQL.user SET user = ‘yourNewRootName’ WHERE user = 'root';To understand the above concept, let us check all the user names and host. The query is as followsmysql> select user, host from MySQL.user;The following is the output+------------------+-----------+ | user | host | +------------------+-----------+ | Bob | % | | Manish | % | | User2 | % ...
Read MoreUsing MySQL SELECT for simple BOOLEAN evaluation?
You can use CASE statement for this. Let us see an example −mysql> create table BooleanEvaluationDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> FirstValue int, -> SecondValue int -> ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into BooleanEvaluationDemo(FirstValue, SecondValue) values(10, 5); Query OK, 1 row affected (0.20 sec) mysql> insert into BooleanEvaluationDemo(FirstValue, SecondValue) values(15, 20); Query OK, 1 row affected (0.16 sec) mysql> insert into BooleanEvaluationDemo(FirstValue, SecondValue) values(50, 40); Query OK, 1 row affected (0.14 ...
Read MoreDisplay IDs in a particular order with MySQL IN()?
To display IDs in a particular order i.e. the order of your choice use FIELD() method.Let us first create a table −mysql> create table DemoTable ( UserId int ); Query OK, 0 rows affected (0.64 sec)Following is the query to insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(80); Query OK, 1 row affected (0.13 sec) ...
Read MoreC++ Program to Find the Maximum Cut in a Graph
In this program to find the maximum Cut in a graph, we need to find the Edge Connectivity of a Graph. An Edge Connectivity of a Graph of a graph means it is a bridge, removing it graph will be disconnected. Number of connected components increases with the removing of bridge in a disconnected undirected graph.Functions and pseudocodeBegin Function connections() is a recursive function to find out the connections: A) Mark the current node un visited. B) Initialize time and low value C) Go through all vertices adjacent to this D) Check if the subtree ...
Read MoreCreate Quartet Tuple from another collection in Java
Use the fromCollection() method to create Quartet Tuple from another collection i.e. we will see an example of List here.Let us first see what we need to work with JavaTuples. To work with Quartet class in JavaTuples, you need to import the following package −import org.javatuples.Quartet;Note − Steps to download and run JavaTuples program If you are using Eclipse IDE to run Quartet Class in JavaTuples, then Right Click Project → Properties → Java Build Path → Add External Jars and upload the downloaded JavaTuples jar file.The following is an example −Exampleimport java.util.*; import org.javatuples.Quartet; public class Demo { ...
Read MoreHow to trim commas with MySQL?
The syntax is as follows to trim commas −SELECT TRIM(BOTH ', ' FROM yourColumnName) from yourTableName;Let us see an example −mysql> create table TrimCommasDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> AllTechnicalSkills text -> ); Query OK, 0 rows affected (0.81 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> insert into TrimCommasDemo(AllTechnicalSkills) values(', C, C++, Java, '); Query OK, 1 row affected (0.14 sec) mysql> insert into TrimCommasDemo(AllTechnicalSkills) values(', MySQL, SQL Server, MongoDB, '); Query OK, 1 row affected (0.13 sec) mysql> ...
Read MoreHow to convert all the records in a MySQL table from uppercase to lowercase?
Convert all the records in a MySQL table from uppercase to lowercase using UPDATE command along with LOWER() method.Let us first create a table −mysql> create table DemoTable ( Id varchar(100), StudentFirstName varchar(20), StudentLastName varchar(20), StudentCountryName varchar(10) ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('STU-101', 'John', 'Smith', 'US'); Query OK, 1 row affected (0.59 sec) mysql> insert into DemoTable values('STU-102', 'John', 'Doe', 'UK'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('STU-103', 'David', 'Miller', 'AUS'); Query OK, 1 ...
Read MorePerform search/replace for only the first occurrence of a character with session variable in MySQL
To perform search/ replace for only the first occurrence, use the CONCAT and REPLACE() function.The query is as follows to set user defined session variable −mysql> set @Sentence='Thks ks is a my string'; Query OK, 0 rows affected (0.00 sec)In this k will be replaced with i only once. The query is as follows. We have used INSTR() also −mysql> select @Sentence as NewString ,CONCAT(REPLACE(LEFT(@Sentence, INSTR(@Sentence, 'k')), 'k', 'i'), -> SUBSTRING(@Sentence, INSTR(@Sentence, 'k') + 1)) as ChangeOnlyOneTime;The following is the output displaying only the first occurrence of a character is replaced −+------------------------+------------------------+ | NewString ...
Read MoreDoes MySQL have an expanded output flag similar PostgreSQL?
Yes, you can get expanded out in MySQL using the /G, instead of semicolon(;). The syntax is as followsSELECT *FROM yourTableName\GLet us first create a table as an examplemysql> create table expandedOutputDemo - > ( - > EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > EmployeeName varchar(20), - > EmployeeAge int - > ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into expandedOutputDemo(EmployeeName, EmployeeAge) values('Larry', 27); Query OK, 1 row affected (0.16 sec) mysql> insert into expandedOutputDemo(EmployeeName, EmployeeAge) values('Mike', 29); Query ...
Read MoreHow to count all characters in all rows of a field in MySQL?
The syntax is as follows to count all characters in all rows of a field −select sum(char_length(yourColumnName)) AS anyAliasName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table CountAllCharactersDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(20), -> UserSubject text -> ); Query OK, 0 rows affected (0.47 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into CountAllCharactersDemo(UserName, UserSubject) values('Larry', 'Introduction To Java'); Query OK, 1 row affected (0.19 ...
Read More