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Articles on Trending Technologies
Technical articles with clear explanations and examples
Light Emitting Diodes (LEDs)\\n
Light can be obtained from various sources like candles, lamp and sunrays etc. Light bulb had invented by Thomas Edison in 1879. An electric current is passed through a filament inside bulb, it gets heated up and emits light when sufficient current is passed through the filament. That means it converts electrical energy into heat energy in the bulb. Where in Light Emitting Diodes (LED), electronic electrical energy can directly converted into light energy.Light is a energy which is released by atoms. Particles of light are photons which have no mass. Atoms are basic building blocks which are made of small ...
Read MoreFind out the records of students with more than a specific score in MySQL?
Set it with WHERE and get the records of students more than a specific score. Let us first create a table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100), -> StudentScore int -> ); Query OK, 0 rows affected (1.65 secInsert some records in the table using insert command −mysql> insert into DemoTable(StudentName, StudentScore) values('John', 43); Query OK, 1 row affected (0.81 sec) mysql> insert into DemoTable(StudentName, StudentScore) values('Sam', 48); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(StudentName, StudentScore) values('Chris', 33); ...
Read MoreMySQL query to get the count of distinct records in a column
To get the count of distinct records, use DISTINCT along with COUNT(). Following is the syntax −select count(DISTINCT yourColumnName) from yourTableName;Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(20), -> Score int -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', 56); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Sam', 89); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('John', 56); Query OK, 1 row affected (0.17 sec) mysql> insert into ...
Read MoreMySQL query to convert timediff() to seconds?
For this, you can use TIME_TO_SEC() function. Let us first create a table −mysql> create table DemoTable -> ( -> SourceTime time, -> DestinationTime time -> ); Query OK, 0 rows affected (1.33 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('10:20:00', '4:50:54'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('12:05:10', '7:45:12'); Query OK, 1 row affected (0.30 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+------------+-----------------+ | SourceTime | DestinationTime | +------------+-----------------+ | 10:20:00 ...
Read MoreHow to filter a specific month in MySQL when date is in varchar?
To filter, you can use STR_TO_DATE() function from MySQL. With that, use MONTH() to get the date from the specific month. Let us first create a table −mysql> create table DemoTable -> ( -> DueDate varchar(100) -> ); Query OK, 0 rows affected (1.18 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('06-19-2019'); Query OK, 1 row affected (0.36 sec) mysql> insert into DemoTable values('01-31-2018'); Query OK, 1 row affected (0.38 sec) mysql> insert into DemoTable values('12-01-2016'); Query OK, 1 row affected (0.14 sec)Display all records from the table using ...
Read MoreHow to sort an alphanumeric column in MySQL?
To sort an alphanumeric column, use LIKE operator along with SUBSTRING(). Let us first create a table −mysql> create table DemoTable -> ( -> StudentId varchar(100) -> ); Query OK, 0 rows affected (1.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('S/TU/100'); Query OK, 1 row affected (0.28 sec) mysql> insert into DemoTable values('S/TU/1000'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values('S/TU/10'); Query OK, 1 row affected (0.47 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following ...
Read MoreHow to use a single MySQL query to count column values ignoring null?
For this, you can COUNT() method, which does not include NULL value. Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(100), -> CountryName varchar(100) -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', null); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Chris', 'US'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Robert', null); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Bob', 'UK'); Query ...
Read MoreImplement MySQL LIMIT and OFFSET in a single query stating its difference
The LIMIT tells about how many records you want while OFFSET gives the records from the given position+1. Let us first create a table −mysql> create table DemoTable -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (1.33 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('Bob'); Query OK, 1 ...
Read MoreRole of CSS :enabled Selector
Use the CSS :enabled selector to style every enabled element. You can try to run the following code to implement the :enabled selector −ExampleLive Demo input:enabled { background: blue; } Subject Student: Age:
Read MoreHow to extract the digit part from the string in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> StudentId varchar(100) -> ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John19383'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Carol9999'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('David123456'); 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 −+-------------+ | StudentId | +-------------+ | John19383 ...
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