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Articles on Trending Technologies
Technical articles with clear explanations and examples
Searching for an integer value in a varchar field in MySQL?
To search for an integer value in a varchar filed, you can use CASE statement.Let us first create a table. Consider, we have a list of email-ids −mysql> create table DemoTable -> ( -> Title varchar(100) -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('9John@example.com'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('3Carol@gmail.com'); Query OK, 1 row affected (0.45 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+-------------------+ | Title ...
Read MoreMySQL query to create table dynamically?
For this, you can use stored procedure. Let us create a table dynamically with two columns i.e. StudentId as int, whereas StudentName as varchar −mysql> DELIMITER $$ mysql> CREATE PROCEDURE creatingDynamicTableDemo(yourTableName VARCHAR(200)) -> BEGIN -> SET @name = yourTableName; -> SET @st = CONCAT(' '> CREATE TABLE IF NOT EXISTS `' , @name, '` ( '> `StudentId` int UNSIGNED NOT NULL AUTO_INCREMENT, '> `StudentName` varchar(20) NOT NULL, '> PRIMARY KEY (`StudentId`) '> ) '> '); -> PREPARE ...
Read MoreQuery MySQL with unicode char code?
Let us first create a table −mysql> create table DemoTable -> ( -> Value int -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(0x41); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(0x30); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(0x61); Query OK, 1 row affected (0.27 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+-------+ | Value | +-------+ | 65 | | ...
Read MoreWhat is the importance of a WindowListener interface in Java?
The class which process the WindowEvent needs to be implemented this interface and an object of this class can be registered with a component by using addWindowListener() method.Methods of WindowListener InterfaceThe WindowListener interface defines 7 methods for handling window eventsvoid windowActivated(WindowEvent we) − Invoked when a window is activated.void windowDeactivated(WindowEvent we) − Invoked when a window is deactivated.void windowOpened(WindowEvent we) − Invoked when a window is opened.void windowClosed(WindowEvent we) − Invoked when a window is closed.void windowClosing(WindowEvent we) − Invoked when a window is closing.void windowIconified(WindowEvent we) − Invoked when a window minimized.void windowDeiconfied(WindowEvent we) − Invoked when a window is restored.Syntaxpublic ...
Read MoreGet the number of rows in a particular table with MySQL
Let us first create a table −mysql> create table DemoTable -> ( -> LastName varchar(100) -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Miller'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Taylor'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Brown'); Query OK, 1 row affected (0.29 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce ...
Read MoreHow to get total occurrences of a value within its own MySQL query?
For this, you can use subquery. Let us first create a table −mysql> create table DemoTable -> ( -> Value int -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.36 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(30); Query OK, ...
Read MoreHow to create and fill a new column in an already created MySQL table?
Let us first create a table −mysql> create table DemoTable -> ( -> Value1 int, -> Value2 int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values(20, 30); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+--------+--------+ | Value1 | Value2 | +--------+--------+ | 10 | 10 | ...
Read MoreHow to remove all instances of a specific character from a column in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> FirstName varchar(100) -> ); Query OK, 0 rows affected (0.41 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam^^^'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('^^^^^^^^Carol'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Robert^^^^^^'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+---------------+ | FirstName | +---------------+ | Adam^^^ ...
Read MoreMySQL query with two boolean conditions to extract date based on hour?
Let us first create a table −mysql> create table DemoTable -> ( -> AdmissionDate datetime -> ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-10 10:45:10'); Query OK, 1 row affected (0.30 sec) mysql> insert into DemoTable values('2019-02-12 20:50:00'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2019-02-12 16:10:19'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+---------------------+ | AdmissionDate ...
Read MoreHow do I select 5 random rows from the 20 most recent rows in MySQL?
For random, use RAND() method. And for limit on rows, use the LIMIT() method.Let us first create a table −mysql> create table DemoTable -> ( -> ShippingDate datetime -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-01'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('2019-01-03'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2019-01-05'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('2019-01-07'); Query OK, 1 row affected (0.11 sec) ...
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