The window.history object is used to go back or to the next page of the web browser. It has the browser's history and comes with the following two methods −history.back − Go to previous URLhistory.next − Go to next URLExampleYou can try to run the following code to learn how ... Read More

It is quite possible to add multiple virtual generated columns in a MySQL table. It can be illustrated with the following example as follows −Examplemysql> Create table profit(cost int, price int, profit int AS (price-cost), price_revised int AS (price-2)); Query OK, 0 rows affected (0.73 sec) mysql> Describe profit; ... Read More

With the help of ALTER EVENT statement along with the RENAME keyword, we can RENAME an existing event. To illustrate it we are having the following example in which we are renaming the event ‘Hello’ to ‘Hello_renamed’ −Examplemysql> ALTER EVENT Hello RENAME TO Hello_renamed; Query OK, 0 rows affected (0.00 ... Read More

Following example uses iterator Method of Collection class to iterate through the HashMap.Example Live Demoimport java.util.*; public class Main {    public static void main(String[] args) {       HashMap< String, String> hMap = new HashMap< String, String>();       hMap.put("1", "1st");       hMap.put("2", "2nd");   ... Read More

Arrays can be compared using following ways in JavaUsing Arrays.equals(array1, array2) methods − This method iterates over each value of an array and compare using equals method.Using Arrays.deepEquals(array1, array2) methods − This method iterates over each value of an array and deep compare using any overridden equals method.Using == on ... Read More

It can be done by using UNIX_TIMESTAMP() function as follows −mysql> Select UNIX_TIMESTAMP(CONCAT(YEAR(CURDATE()), '-01-01')); +--------------------------------------------------+ | UNIX_TIMESTAMP(CONCAT(YEAR(CURDATE()), '-01-01')) | +--------------------------------------------------+ | 1483209000                                       | +--------------------------------------------------+ 1 row in set (0.03 sec)It can ... Read More

A subquery is best defined as a query within a query. Subqueries enable you to write queries that select data rows for criteria that are actually developed while the query is executing at runtime. More formally, it is the use of a SELECT statement inside one of the clauses of ... Read More

As we know that CONCAT() function returns NULL if any of the arguments is NULL but CONCAT_WS() function returns NULL only if the first argument i.e. the separator is NULL and it ignores any other NULL. We can say this is the advantage of CONCAT_WS() function over CONCAT() function when ... Read More

MySQL CHAR() function will ignore NULL if it is provided as an argument to it. To understand it, consider the following examples −mysql> Select CHAR(65, 66, 67, NULL); +---------------------+ | CHAR(65, 66, 67, NULL) | +---------------------+ | ABC                 | +---------------------+ 1 row ... Read More

With Java 9, new factory methods are added to Set interface to create immutable instances. These factory methods are convenience factory methods to create a collection in less verbose and in concise way.Old way to create collectionsExampleimport java.util.Collections; import java.util.HashSet; import java.util.Set; public class Tester {    public static ... Read More