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Writing inner joins with the help of comma operator is the most basic way to combine two tables. As we know that we can also write inner join by using keyword INNER JOIN or synonyms like JOIN. To form an inner join we need to specify a particular condition which is known as join-predicate and while writing inner joins using the comma operator, we use WHERE clause, the only way, to specify the join condition. To understand it, we are taking the example of two tables named tbl_1 and tbl_2 which are having following data:mysql> Select * from tbl_1; +----+--------+ ... Read More
A JTextArea is a multi-line text component to display text or allow the user to enter the text and it will generate a CaretListener interface when we are trying to implement the functionality of the JTextArea component. A JTextArea class inherits the JTextComponent class in Java.In the below example, we can implement a JTextArea class with a user can select either word wrap or line wrap checkboxes using the ItemListener interface.Exampleimport javax.swing.*; import java.awt.*; import java.awt.event.*; public class JTextAreaTest { public static void main(String[] args ) { EventQueue.invokeLater(new Runnable() { @Override public void run() { ... Read More
A GridBagLayout is a very flexible layout manager that allows us to position the components relative to one another using constraints. Each GridBagLayout uses a dynamic rectangular grid of cells with each component occupying one or more cells called its display area. Each component managed by a GridBagLayout is associated with a GridBagConstraints instance that specifies how the component is laid out within its display area. GridBagConstraintsWe can customize a GridBagConstraints object by setting one or more of its public instance variables. These variables specify the component location, size, growth factor, anchor, inset, filling, and padding.gridx: An int value that specifies the leftmost cell that the ... Read More
MySQL REVERSE() function can have the column name as an argument to invert its value. If we want to apply some condition/s then it can be used along with WHERE clause as follows:Examplemysql> Select Name, REVERSE(Name) from Student; +---------+---------------+ | Name | REVERSE(Name) | +---------+---------------+ | Aarav | varaA | | Gaurav | varuaG | | Gaurav | varuaG | | Harshit | tihsraH | | Yashraj | jarhsaY | +---------+---------------+ 5 rows in set (0.00 sec)The above query inverts the values ... Read More
With the help of MySQL string function ASCII(), we can get the number code of a particular character. Its syntax is ASCII(str) where, str, the argument of ASCII() function, is the string whose ASCII value of the first character to be retrieved.It will return the number code the left the most character i.e. first character of the string given as argument.Examplemysql> Select ASCII('T'); +------------+ | ASCII('T') | +------------+ | 84 | +------------+ 1 row in set (0.01 sec) mysql> Select ASCII('t'); +------------+ | ASCII('t') | +------------+ | 116 | +------------+ 1 row ... Read More
If we want to replace strings in multiple records then REPLACE() function must have the column name as 1st argument i.e. at the place of string. It means that, it will replace all the substring with another substring in that particular column. We can also use REPLACE() function with WHERE clause along with UPDATE statement to apply conditions. It is exhibit with the following example:Examplemysql> Update Student set Name = REPLACE(Name, 'G', 'S') WHERE Subject LIKE '%Comp%'; Query OK, 2 rows affected (0.08 sec) Rows matched: 2 Changed: 2 Warnings: 0The above query replaces strings in multiple records of Student ... Read More
As we know that REPLACE () function is used to replace the occurrences of a substring with another substring within a string. We can also use REPLACE function with UPDATE statement to update the table by finding and replacing the data.Examplemysql> Update Student set Father_Name = REPLACE(Father_Name, 'Mr.', 'Shri '); Query OK, 5 rows affected (0.06 sec) Rows matched: 5 Changed: 5 Warnings: 0 mysql> Select Name, Father_Name from Student; +---------+-----------------+ | Name | Father_Name | +---------+-----------------+ | Gaurav | Shri Ramesh | | Aarav | Shri Sanjay | | Harshit ... Read More
MySQL REPLACE() function can replace all the occurrences of a substring with another substring within a string.SyntaxREPLACE(str, find_string, replace_with)Here Str is a string which have the substring.Find_string is a substring which is present one or more times within the strung str.Replace_with is a substring which will replace every time it finds find_string within str.Examplemysql> Select REPLACE('Ram, My Name is Ram', 'Ram', 'Shyam'); +------------------------------------------------+ | REPLACE('Ram, My Name is Ram', 'Ram', 'Shyam') | +------------------------------------------------+ | Shyam, My Name is Shyam | +------------------------------------------------+ 1 row in set (0.00 sec)
In this case, MySQL will not pad anything and truncate the characters from the original string up to the value of length provided as the argument in LPAD() or RPAD() functions.Examplemysql> Select LPAD('ABCD',3,'*'); +--------------------+ | LPAD('ABCD',3,'*') | +--------------------+ | ABC | +--------------------+ 1 row in set (0.00 sec) mysql> Select RPAD('ABCD',3,'*'); +--------------------+ | RPAD('ABCD',3,'*') | +--------------------+ | ABC | +--------------------+ 1 row in set (0.00 sec)We can observe from the above example that both the functions do not pad ‘*’ and truncate the original string up to the length specified i.e. 3 as the argument.
Suppose if we want to make the output of REPEAT() function more readable then we can use another function/s with it. For example, if we want to add space or some other character between the repeated values then we can use CONCAT() function.Examplemysql> Select REPEAT(CONCAT(' *', Subject, '* '), 3)AS Subject_repetition from student; +-----------------------------------------+ | Subject_repetition | +-----------------------------------------+ | *Computers* *Computers* *Computers* | | *History* *History* *History* | | *Commerce* *Commerce* *Commerce* | | *Computers* *Computers* *Computers* | ... Read More