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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL query to get first two highest column values from a table?
To get the first two highest columns, use ORDER BY. With that, use LIMIT 2 to get only the first 2 −select *from yourTableName order by yourColumnName DESC LIMIT 2;Let us first create a table −mysql> create table DemoTable -> ( -> Value int -> ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(90); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(70); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected ...
Read MoreHow to get the primary key "column name" of a specific table in MySQL?
Let us first create a table wherein we have a Primary Key CustomerId −mysql> create table DemoTable ( CustomerId int NOT NULL AUTO_INCREMENT, CustomerName varchar(20), CustomerAge int, CustomerCountryName varchar(100), PRIMARY KEY(CustomerId) ); Query OK, 0 rows affected (0.94 sec)Following is the query to get the primary key “column name” of a specific table in MySQL −mysql> SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME = 'DemoTable' AND CONSTRAINT_NAME = 'PRIMARY';This will produce the following output −+-------------+ | COLUMN_NAME | +-------------+ | CustomerId | +-------------+ 1 row in set, 2 warnings (0.12 sec)
Read MoreJava ResultSet getRow() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.The getRow() method of the ResultSet interface retrieves the current row number/position of the ResultSet pointer.This method returns an integer value representing the current row number to which the ResultSet pointer points to.ExampleLet us ...
Read MoreNew line separator doesn't work for group_concat function in MySQL? How to use it correctly?
To use new line separator in group_concat() function, follow the below syntax −select group_concat(concat_ws(' ', yourColumnName1, yourColumnName2) SEPARATOR "\r") from yourTableName;Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(20), LastName varchar(20) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstName, LastName) values('John', 'Smith'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(FirstName, LastName) values('David', 'Miller'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(FirstName, LastName) values('John', 'Doe'); ...
Read MoreHow to work with border layout position options in Java?
Let us see some examples to work with different border layout position options such as PAGE_START, PAGE_END, etc.The following is an example of BorderLayout.PAGE_START option −Examplepackage my; import java.awt.BorderLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JPanel; import javax.swing.JTextArea; import javax.swing.JToolBar; public class SwingDemo { public static void main(String[] args) { JPanel panel = new JPanel(new BorderLayout()); JToolBar toolbar = new JToolBar(); panel.add(toolbar, BorderLayout.PAGE_START); toolbar.add(new JTextArea(" Add name here")); toolbar.add(new JButton("Submit Name")); toolbar.addSeparator(); toolbar.add(new JTextArea(" Add age here")); ...
Read More8085 program to subtract two consecutive bytes of an array
Here we will see how we can subtract two consecutive elements in an array using 8085.Problem StatementWrite 8085 program to subtract two consecutive elements of an array and store them in the same location. The results will be placed at the same location from where they are taken. The numbers are stored from location 8001. The size of array is stored at 8000.DiscussionHere we will solve this problem by using one subroutine. That will subtract two consecutive numbers and stored them into correct position. That subroutine will be called multiple times to subtract all consecutive pairs. The task will be ...
Read MoreMySQL select any one field out of two with respect to the value of a third field?
For this, use IF(). Let us first create a table −mysql> create table DemoTable -> ( -> PlayerName varchar(100), -> PlayerScore int, -> PlayerStatus varchar(100) -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', 88, 'BAD'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Chris', 78, 'BAD'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('Robert', 90, 'BAD'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('David', 80, 'BAD'); Query ...
Read MoreJava ResultSet getMetaData() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.The ResultSetMetaData provides information about the obtained ResultSet object like, the number of columns, names of the columns, datatypes of the columns, name of the table etc…The getMetaData() method of ResultSet interface ...
Read MoreSelect last 3 rows from database order by id ASC?
You can use subquery. Following is the syntax −SELECT * FROM ( SELECT * FROM yourTableName ORDER BY yourIdColumnName DESC LIMIT 3 ) anyAliasName ORDER BY yourIdColumnName;Let us first create a table −mysql> create table DemoTable ( ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientName varchar(100) ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(ClientName) values('Larry'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(ClientName) values('Chris'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(ClientName) values('Bob'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(ClientName) values('David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(ClientName) values('Carol'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(ClientName) values('Robert'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(ClientName) values('Sam'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(ClientName) values('Mike'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce ...
Read More8085 program to take all numbers whose D7 and D1 are 0
Here we will see how we can take all numbers whose D7 and D1 bits are 0, using 8085.Problem StatementWrite 8085 program to take all numbers from an array whose D7 and D1 bits are 0. Numbers are stored from 8001, and the array size is stored at 8000. Store the result from 9000 onwards.DiscussionTo solve this problem, we will AND the number by 82H (1000 0010). If the result is 0, then the number is acceptable. If the bit position D7 and D1 are 0, then only the result will be 0.InputAddressData……80000A8001E98002D38003618004AD80052A80061F80075D8008A68009A9800A35…… Flow Diagram ProgramAddressHEX CodesLabelsMnemonicsCommentsF00021, 00, 80 LXI H, 8000Load the ...
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