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Articles by karthikeya Boyini
Page 123 of 143
How to display message from a stored procedure?
To display message from stored procedure on the basis of conditions, let us use IF-ELSE condition −mysql> DELIMITER // mysql> CREATE PROCEDURE showMessage(value int, Name varchar(20)) BEGIN IF(value > 100) then SELECT CONCAT("HELLO", " ", Name); ELSE SELECT CONCAT("BYE", " ", Name); END IF; END // Query OK, 0 rows affected (0.18 sec) mysql> DELIMITER ;Case 1 − Call the stored procedure using CALL command, when value is more than 100 −call showMessage(200, 'John');This will produce ...
Read MoreMySQL query to select too many rows?
You can use LIMIT for this, which is used to fetch limited number of records. Let us first create a table −mysql> create table DemoTable ( Id int, Name varchar(20) ); Query OK, 0 rows affected (0.53 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(10, 'John'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(11, 'Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(12, 'David'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(13, 'Carol'); Query OK, 1 row affected (0.13 sec) mysql> ...
Read MoreReplace 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 MoreHeap overflow and Stack overflow in C
Heap OverflowHeap is used to store dynamic variables. It is a region of process’s memory. malloc(), calloc(), resize() all these inbuilt functions are generally used to store dynamic variables.Heap overflow occurs when −A) If we allocate dynamic large number of variables −int main() { float *ptr = (int *)malloc(sizeof(float)*1000000.0)); }B) If we continuously allocate memory and do not free after using it.int main() { for (int i=0; i
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; ...
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