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Articles by Samual Sam
Page 105 of 151
How can we overcome the property of CONCAT() function that it returns NULL if any one of the argument is NULL, especially when we want to concatenate the values from the column and any of the columns have NULL as its value?
Problem Statement How can we overcome the property of CONCAT() function that it returns NULL if any one of the argument is NULL, especially when we want to concatenate the values from the column and any of the columns have NULL as its value? The above-said property is not useful especially in the case when we want to concatenate the values from the column and any of the columns have NULL as its value. To overcome this, we can use IFNULL() function along with CONCAT() function. To ...
Read MoreHow does the precedence of || operator depend on PIPES_AS_CONCAT SQL mode?
As we know that in MySQL by default || operator is a logical OR operator but it depends upon PIPES_AS_CONCAT SQL mode. If PIPES_AS_CONCAT SQL mode is enabled, then || operator works as string concatenation. At that time its precedence would be between ^ and the unary operator. Following example will make it understand −mysql> Set @C='tutorials'; Query OK, 0 rows affected (0.00 sec) mysql> Set @D='point'; Query OK, 0 rows affected (0.00 sec) mysql> Select @C||@D; +--------+ | @C||@D | +--------+ | 1 | +--------+ 1 row in set (0.00 sec)The result set of the ...
Read MoreHow MySQL evaluates when I use a conditional expression within SUM() function?
As we know that, by using a conditional expression within SUM() function we can get the number of rows that meet the condition. So, in this case, MySQL evaluates to 1 each time the condition is true and 0 each time it is false.To understand it, consider the following example of table ‘employee’, having the following details −mysql> Select * from Employee; +----+--------+--------+ | ID | Name | Salary | +----+--------+--------+ | 1 | Gaurav | 50000 | | 2 | Rahul | 20000 | | 3 | Advik | 25000 ...
Read MoreHow can we use MySQL POWER() function with the column's data values?
If we want to use POWER() function with column’s data values then the first argument i.e. the base would be the name of the column and the second argument i.e. the exponent would be as specified by us. To understand it considers a table ‘Employee’ having the following records −mysql> Select * from Employee; +----+--------+--------+ | ID | Name | Salary | +----+--------+--------+ | 1 | Gaurav | 50000 | | 2 | Rahul | 20000 | | 3 | Advik | 25000 | | 4 | Aarav | 65000 | | 5 | Ram | 20000 | ...
Read MoreHow can I use SUBSTRING_INDEX() function to get the substring as output which is between two same delimiters in a string?
We need to use nested SUBSTRING_INDEX() function for getting the substring as output which is between two same delimiters in a string. For example, from the string ‘www.tutorialspoint.com’, we want the substring ‘tutorialspoint’, which is in between two same delimiters ‘.’ as output then SUBSTRING_INDEX() function can be used in nested form as follows −mysql> Select SUBSTRING_INDEX(SUBSTRING_INDEX('www.tutorialspoint.com','.',2),'.',-1)AS 'Nested SUBSTRING_INDEX'; +------------------------+ | Nested SUBSTRING_INDEX | +------------------------+ | tutorialspoint | +------------------------+ 1 row in set (0.02 sec)
Read MoreWhat happens with the output of MySQL EXPORT_SET() function if I will skip the value of the fifth argument i.e. a number of bits?
Actually, the default value of the fifth argument i.e. number of bits is 64, hence if we will not specify any value on fifth argument them MySQL will check the bits up to 64 bits and produce the result. It can be understood from the following example −Examplemysql> SELECT EXPORT_SET(5, 'Y', 'N', ' ')\G *************************** 1. row *************************** EXPORT_SET(5, 'Y', 'N', ' '): Y N Y N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N ...
Read MoreHow can we add values into the columns of a MySQL table?
INSERT command is used to add values to the columns of a MySQL table. We need to specify the values in INSERT command for all the columns as follows −SyntaxINSERT INTO table_name values(value1, value2, …)ExampleSuppose we have a table named ‘Stock’ with three columns ‘Item_id’, ‘Item_name’ and ‘Item_rate’ then with the help of following query we can add values in these columns.mysql> INSERT INTO Stock values(1, 'HistoryBook', 250); Query OK, 1 row affected (0.07 sec) mysql> INSERT INTO Stock values(2, 'DBMSBook', 280); Query OK, 1 row affected (0.10 sec) mysql> Select * from Stock; +---------+-------------+-----------+ | item_id | ...
Read MoreHow can I see the constraints which are applied to a table stored in the database I am currently using?
MySQL SHOW CREATE TABLE statement will provide us the constraints applied to a particular table along with some other details about that table. Its syntax would be as follows −SyntaxSHOW CREATE TABLE table_name;Here table_name is the name of the table on which we want to see the constraints.ExampleIn this example we are getting the detail of the table named ‘employees’ −mysql> Show Create table employees\G *************************** 1. row *************************** Table: employees Create Table: CREATE TABLE `employees` ( `Id` int(11) NOT NULL AUTO_INCREMENT, `Name` varchar(35) DEFAULT NULL, PRIMARY KEY (`Id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 1 ...
Read MoreCreate translucent windows in Java Swing
With JDK 7, we can create a translucent window using swing very easily. With following code, a JFrame can be made translucent.// Set the window to 55% opaque (45% translucent). frame.setOpacity(0.55f);ExampleSee the example below of a window with 55% translucency.import java.awt.GridBagLayout; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.SwingUtilities; public class Tester { public static void main(String[] args) { JFrame.setDefaultLookAndFeelDecorated(true); // Create the GUI on the event-dispatching thread SwingUtilities.invokeLater(new Runnable() { @Override public void ...
Read MoreHow can we remove multicolumn UNIQUE indexes?
Multicolumn UNIQUE indexes can also be removed in the same as we remove UNIQUE constraint from the table.ExampleIn this example, with the following query we have removed the multicolumn UNIQUE indexes on table ‘employee’ −mysql> DROP index id_fname_lname on employee; Query OK, 0 rows affected (0.30 sec) Records: 0 Duplicates: 0 Warnings: 0The removal of UNIQUE indexes can be observed from the result sets of the following query −mysql> show index from employee; Empty set (0.00 sec) mysql> describe employee; +------------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | ...
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