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Articles by karthikeya Boyini
Page 124 of 143
MySQL 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 ...
Read MoreHow to use pop() 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 pop() 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 MoreHow to use put() 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 put() 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 text view to show PriorityBlockingQueue elements.Step ...
Read MoreHow to use remainingCapacity() in android LinkedBlockingDeque?
Before getting into the example, we should know what LinkedBlockingDeque is. It is implemented by Collection interface and the AbstractQueue class. It provides optional boundaries based on linked nodes. It going to pass memory size to a constructor and helps to provide memory wastage in android.This example demonstrates about How to use remainingCapacity() in android LinkedBlockingDequeStep 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 ...
Read MoreHow to use remove() in android ConcurrentLinkedQueue?
Before getting into an example, we should know what ConcurrentLinkedQueue is, it is an unbounded queue based on linked nodes. Multiple threads can access queue elements with safety. Elements travel based on queue strategy as FIFO and elements going to insert from a tail. It does not allow null values.This example demonstrates about How to use remove() in android ConcurrentLinkedQueueStep 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, ...
Read MoreHow to use remove() in android CopyOnWriteArraySet?
Before getting into the example, we should know what CopyOnWriteArraySet is. It is a thread-safe variant of ArrayList and operations add, set, and so on by making a fresh copy of the underlying array.This example demonstrates about How to use remove () in android CopyOnWriteArraySetStep 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 CopyOnWriteArraySet elements.Step 3 − Add the following ...
Read MoreSelect MySQL rows where column contains same data in more than one record?
Use MySQL JOIN to select MySQL rows where column contains same data in more than one record. Let us first create a table −mysql> create table DemoTable ( UserId int, UserName varchar(20) ); Query OK, 0 rows affected (0.54 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(10, 'John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(11, 'Sam'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values(12, 'Larry'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(13, 'David'); Query OK, 1 row affected (0.17 ...
Read MoreMySQL order by 0 first and then display the record in descending order?
In order to order by 0 first and then largest, you can use the below syntax −select *from yourTableName order by yourColumnName=0 DESC, yourColumnName DESC;Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.65 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(90); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.12 ...
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