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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to find last date from records with date values in MySQL?
To get the last date i.e. the latest, use aggregate function MAX() with a subquery. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, ExpiryDate date ); Query OK, 0 rows affected (1.40 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(ExpiryDate) values('2018-12-31'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(ExpiryDate) values('2019-09-01'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(ExpiryDate) values('2019-09-01'); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable(ExpiryDate) values('2016-08-30'); Query OK, 1 row affected (0.13 ...
Read MoreIs it compulsory to set PRIMARY KEY for AUTO_INCREMENT value?
Yes, use AUTO_INCREMENT with PRIMARY KEY. Let us first create a table −mysql> create table DemoTable ( EmployeeId int NOT NULL AUTO_INCREMENT, EmployeeName varchar(40), EmployeeAge int, PRIMARY KEY(EmployeeId), UNIQUE KEY(EmployeeName, EmployeeAge) ); Query OK, 0 rows affected (0.96 sec)Let us check the table description of the table −mysql> desc DemoTable;This will produce the following output −+--------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +--------------+-------------+------+-----+---------+----------------+ | EmployeeId | int(11) | NO | PRI | NULL ...
Read MoreMySQL query to find the average of only first three values from a column with five values
For this, you can use a subquery. Let us first create a table −mysql> create table DemoTable ( Score int ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(80); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(45); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(55); Query OK, 1 row affected (0.33 sec) mysql> insert into DemoTable values(78); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(88); Query OK, 1 row affected (0.13 sec)Display all records from ...
Read MoreMySQL query to display record with maximum count values in a group with other column values?
For this, use the GROUP BY HAVING clause. Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(88); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(88); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(88); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(99); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(99); Query OK, 1 row affected (0.09 sec) mysql> insert ...
Read MoreHow to count specific comma separated values in a row retrieved from MySQL database?
To count comma-separated-values, use aggregate function COUNT(*) along with FIND_IN_SET(). Let us first create a table −mysql> create table DemoTable ( Value varchar(100) ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('10, 20, 60, 80'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('60, 70, 90'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('50, 55, 65, 60'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('90, 98, 97'); Query OK, 1 row affected (0.12 sec)Display all records ...
Read MoreIs there anything like substr_replace in MySQL?
For this, use the INSERT() function from MySQL. The INSERT(str, pos, len, newstr) returns the string str, with the substring beginning at position pos and len characters long replaced by the string newstr. Returns the original string if pos is not within the length of the string.It replaces the rest of the string from position pos if len is not within the length of the rest of the string. Returns NULL if any argument is NULL.Let us first create a table −mysql> create table DemoTable ( Password varchar(50) ); Query OK, 0 rows affected (0.51 sec)Insert some records in ...
Read MoreImplement MySQL conditional GROUP BY with NOT IN to filter records from duplicate column values
Let us first create a table −mysql> create table DemoTable ( Name varchar(40), Score int ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam', 89); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('Adam', 89); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Chris', 89); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Chris', 89); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Bob', 98); Query OK, 1 row affected (0.10 sec) mysql> insert ...
Read MoreFinding average marks of students for different subjects and display only the highest average marks in MySQL
For this, you can use subquery. Let us first create a table −mysql> create table DemoTable ( StudentName varchar(40), StudentMarks int ); Query OK, 0 rows affected (0.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam', 56); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Chris', 78); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Adam', 89); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Robert', 98); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Chris', 65); Query OK, 1 ...
Read MoreC++ program to find cabs nearby using Great Circle Distance formula
In this article, we will be discussing a program to find the cabs near about (less than 50km) using the Great Circle Distance formula.Let us suppose we have been given a JSON file which contains the name and coordinates of the people who need a cab and also the coordinates of the all the cabs available.To solve this, we would convert the GPS coordinates into double. From the double form, we would finally convert them in degrees to radians. Then we can ultimately apply the Great Circle Distance formula to find the cabs available in 50km from the user’s position.Note ...
Read MoreMySQL query to get count of each fileid entry in a table with Id and FileIDs?
Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FileID int ) AUTO_INCREMENT=100; Query OK, 0 rows affected (1.36 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FileID) values(50); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(FileID) values(60); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(FileID) values(50); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(FileID) values(70); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(FileID) values(60); Query OK, 1 row affected (0.28 sec) mysql> ...
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