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Articles by karthikeya Boyini
Page 127 of 143
Replace dot with comma on MySQL SELECT?
To replace dot with comma on SELECT, you can use REPLACE(). Following is the syntax −select replace(yourColumnName, '.' , ', ' ) from yourTableName;Let us first create a table −mysql> create table DemoTable ( Value float ); Query OK, 0 rows affected (0.63 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(4.56); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(456.23); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(1078.3); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(2000.50); Query OK, 1 row affected (0.26 sec) mysql> ...
Read MoreHow to remove Duplicate Records except a single record in MySQL?
You can use DELETE command with some condition for this since we need to keep one record and delete rest of the duplicate records.Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(40) ); Query OK, 0 rows affected (0.48 sec)Insert records in the table using insert command −mysql> insert into DemoTable(StudentName) values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(StudentName) values('Carol'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(StudentName) values('Sam'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable(StudentName) ...
Read MoreHow to use Iterator to loop through the Map key set?
First, create a HashMap, which is to be iterated −Mapmap = new LinkedHashMap(); map.put("Jack", "0"); map.put("Tim", "1"); map.put("David", "2"); map.put("Tom", "3"); map.put("Kevin", "4");Now, use Iterator to map through keyset −Iterator iterator = map.keySet().iterator();Iterate through all the pairs −while (iterator.hasNext()) { String resKey = (String) iterator.next(); System.out.println("Rank of " + resKey + " is " + map.get(resKey)); }Example Live Demoimport java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; public class Demo { public static void main(String[] args) { Mapmap = new LinkedHashMap(); map.put("Jack", "0"); map.put("Tim", "1"); map.put("David", "2"); ...
Read MoreSet MySQL int column to auto increment by 1 beginning at 10000?
Let us first create a table. Here, we have set UserId as AUTO_INCREMENT PRIMARY KEY −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY ); Query OK, 0 rows affected (0.72 sec)Following is the query to set int column to auto increment by 1 beginning at 10000 −mysql> alter table DemoTable AUTO_INCREMENT=10000; Query OK, 0 rows affected (0.31 sec) Records: 0 Duplicates: 0 Warnings: 0Insert records in the table using insert command −mysql> insert into DemoTable values(); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.19 sec) ...
Read MoreHow to use poll() in android PriorityBlockingQueue?
Before getting into the example, we should know what PriorityBlockingQueue is. It is an unbounded queue and follows the same order as a priority queue. The main usage of priority blocking queue is, it going to handle out of memory error.This example demonstrates about How to use poll() in android PriorityBlockingQueueStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show PriorityBlockingQueue ...
Read MoreHow to subtract by 1 if the field value > 0 in MySQL?
You can use CASE statement with UPDATE command for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Value int ); Query OK, 0 rows affected (1.44 sec)Insert records in the table using insert command −mysql> insert into DemoTable(Value) values(100); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable(Value) values(0); Query OK, 1 row affected (4.16 sec) mysql> insert into DemoTable(Value) values(104); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(Value) values(0); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Value) values(5); Query ...
Read MoreHow to use pollLast() in android ConcurrentLinkedDeque?
Before getting into an example, we should know what ConcurrentLinkedDeque is, it is unbounded deque based on linked nodes. Multiple threads can access deque elements with safety.This example demonstrates about How to use pollLast() in android ConcurrentLinkedDequeStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show ConcurrentLinkedDeque elements.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Build; import android.os.Bundle; ...
Read MoreMySQL query to check if database is empty or not?
You can use INFORMATION_SCHEMA.COLUMNS to check if a database is empty or not. The syntax is as follows −SELECT COUNT(DISTINCT `TABLE_NAME`) AS anyAliasName FROM `INFORMATION_SCHEMA`.`COLUMNS` WHERE `table_schema` = 'yourDatabaseName';The above syntax returns 0 if the database has notable otherwise it returns the number of tables. For our example, we are using the databases ‘sample’ and ‘test3’, which we created before.The first database ‘sample’ has more tables, therefore the above query will return a number of tables. The second database ‘test3’ does not have any tables, therefore the above query will return 0.Case 1 − Database sampleThe query is as follows ...
Read MoreHow to use pool() ArrayBlockingQueue in android?
Before getting into an example, we should know what arrayblockingqueue is, it travels FIFO manner and the first element going to live the longest period of time and last element of the queue going to live a short period of the time.This example demonstrates about How to use pool() ArrayBlockingQueue in androidStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken a text view to show ...
Read MoreGet total in the last row of MySQL result?
To get total in the last row of MySQL result, use the following syntax −( SELECT yourColumnName1, yourColumnName2, yourColumnName3, . . N FROM yourTableName ) UNION ( SELECT "yourMessage" AS anyAliasName1, SUM(yourColumnName1) AS anyAliasName2, SUM(yourColumnName2) AS anyAliasName3, . . N FROM yourTableName );To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table ProductDemo -> ( -> ProductId varchar(10), -> ProductQuantity int, -> ProductValue int -> ); Query OK, 0 ...
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