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Articles by karthikeya Boyini
Page 101 of 142
How can we use MySQL SUM() function with HAVING clause?
By using MySQL SUM() function with the HAVING clause, it filters the result based on a specific condition given after the HAVING clause. To understand the above concept, consider an ‘employee_tbl’ table, which is having the following records −mysql> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | 2007-05-27 | 220 | | 3 | Jack | 2007-05-06 | ...
Read MoreHow can we distinguish between MySQL IFNULL() and NULLIF() functions?
Actually, both MySQL IFNULL() and NULLIF() functions are having an almost same syntax as given below −The syntax of IFNULL()IFNULL(expression1, expression2)The syntax of NULLIF()NULLIF(expression1, expression2)They can be distinguished in the way they return the first argument as result. IFNULL() function will return the first argument as a result if it is not NULL and NULLIF() function will return the first argument as a result if both the arguments are not same.mysql> Select IFNULL('Ram', 'Shyam'); +-----------------------+ | IFNULL('Ram', 'Shyam') | +-----------------------+ | Ram | +-----------------------+ 1 row in set (0.00 sec) mysql> Select ...
Read MoreHow can I use IFNULL() function at the place of COALESCE() function in MySQL?
As we know that IFNULL() function will return the first argument if it is not NULL otherwise it returns the second argument. On the other hand, COALESCE() function will return first non-NULL argument. Actually, both IFNULL() and COALESCE() functions in MySQL works equivalently if the number of arguments is two only. The reason behind this is that IFNULL() function accepts only two arguments and in contrast, COALESCSE() function can accept any number of arguments.Suppose if we want to use IFNULL() function at the place of COALESCE() function then the number of arguments must be two. Following example will demonstrate it ...
Read MoreWhat MySQL ELT() function returns if the index number, provided as an argument, is higher than the number of strings?
MySQL ELT() function returns NULL as output if the index number provided as argument is higher than the number of strings. Following is an example to make it clearer −Examplemysql> Select ELT(6,'Ram','is','a','good','boy')As Result; +--------+ | Result | +--------+ | NULL | +--------+ 1 row in set (0.00 sec)As we can see that index number is 6 and the list of strings is having only 5 strings. Hence MySQL returns NULL.
Read MorePython Regex to extract maximum numeric value from a string
The easiest way to extract the maximum numeric value from a string using regex is to −Use the regex module to extract all the numbers from a stringFind the max from these numbersFor example, for the input string −There are 121005 people in this city, 1587469 in the neighboring city and 18775994 in a far-off city.We should get the output −18775994We can use "\d+" regex to find all numbers in a string as \d signifies a digit and the plus sign finds the longest string of continuous digits. We can implement it using the re package as follows −import re ...
Read MoreWhat MySQL returns if sub-query, used to assign new values in the SET clause of UPDATE statement, returns multiple rows?
In this case, MySQL will return an error message because we know that if sub-query is used to assign new values in the SET clause of UPDATE statement then it must return exactly one row for each row in the update table that matches the WHERE clause.Examplemysql> insert into info(id, remarks) values(5, 'average'); Query OK, 1 row affected (0.06 sec) mysql> select * from info; +------+-----------+ | id | remarks | +------+-----------+ | 1 | Good | | 2 | Good | | 3 | Excellent | | 4 ...
Read MoreHow can we sort MySQL output in ascending order?
We need to specify ASC (short form for ASCENDING) keyword in ORDER BY clause if we want to sort out the result set in ascending order.SyntaxSelect column1, column2,…,columN From table_name ORDER BY column1[column2,…] ASC;ExampleIn the following example, we have sorted the result set by column ‘Name’ in the ascending order.mysql> Select * from Student ORDER BY Name ASC; +------+---------+---------+-----------+ | Id | Name | Address | Subject | +------+---------+---------+-----------+ | 2 | Aarav | Mumbai | History | | 1 | Gaurav | Delhi | Computers | | 15 | Harshit | Delhi | Commerce | | 17 | Raman | Shimla | Computers | +------+---------+---------+-----------+ 4 rows in set (0.00 sec)
Read MoreDatabase operations in Java
This article provides an example of how to create a simple JDBC application. This will show you how to open a database connection, execute a SQL query, and display the results.Creating JDBC ApplicationThere are following six steps involved in building a JDBC application −Import the packages: Requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.Register the JDBC driver: Requires that you initialize a driver so you can open a communication channel with the database.Open a connection: Requires using the DriverManager.getConnection() method to create a Connection object, which represents ...
Read MoreCounting number of paragraphs in text file using java
We can read paragraphs in a file by reading it in a string and then spilting based on "\r" pattern. See the example below −ExampleConsider the following text file in the classpath.test.txtThis is Line 1 This is Line 2 This is Line 3 This is Line 4 This is Line 5 This is Line 6 This is Line 7 This is Line 8 This is Line 9 This is Line 10Tester.javaimport java.io.File; import java.io.FileInputStream; import java.io.IOException; public class Tester { public static void main(String args[]) throws IOException { FileUtil fileUtil = ...
Read MoreCounting number of characters in text file using java
We can read characters in a file using BufferedReader class of Java. See the example below −ExampleConsider the following text file in the classpath.test.txtThis is Line 1 This is Line 2 This is Line 3 This is Line 4 This is Line 5 This is Line 6 This is Line 7 This is Line 8 This is Line 9 This is Line 10Tester.javaimport java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStreamReader; public class Tester { private static final String FILE_PATH = "data.txt"; public static void main(String args[]) throws IOException { ...
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