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Articles on Trending Technologies
Technical articles with clear explanations and examples
Find average on the basis of corresponding duplicate VARCHAR values in MySQL
Let us first create a table −mysql> create table DemoTable( Value int, Value2 varchar(100) ); Query OK, 0 rows affected (0.84 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, '999.999.999.999'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(20, '888.888.888.888'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(30, '999.999.999.999'); Query OK, 1 row affected (0.09 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-------+-----------------+ | Value | Value2 ...
Read MoreCan we perform MySQL UPDATE and change nothing in a table?
Yes, we can do that. Let us first create a table −mysql> create table DemoTable( Id int ); Query OK, 0 rows affected (1.02 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(201); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(202); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(290); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(301); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------+ ...
Read MoreWhat does select @@identity do in MySQL?
The @@identity returns the last inserted value in the auto_increment column in the current session. Let us first create a table −mysql> create table DemoTable( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserName varchar(100) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName) values('David'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(UserName) values('Mike'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(UserName) values('Carol'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(UserName) values('Robert'); Query OK, 1 row affected (0.24 sec) ...
Read MoreMySQL query to fetch the maximum corresponding value from duplicate column values
Let us first create a table −mysql> create table DemoTable( ProductName varchar(100), ProductPrice int ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Product-1', 56); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Product-2', 78); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('Product-1', 88); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Product-2', 86); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Product-1', 45); Query OK, 1 row affected (0.18 sec) mysql> insert into ...
Read MoreWill extending the size of a varchar field in MySQL affect the data inside it?
If you will extend the size of a varchar field in MySQL then it won’t affect the data inside it.Let us first create a table −mysql> create table DemoTable( Name varchar(8) ); Query OK, 0 rows affected (1.11 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Robert'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Mike'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.13 sec)Display all records from the ...
Read MoreSort a list in MySQL and display a fixed result at the end of the column?
Let us first create a table −mysql> create table DemoTable( FirstName varchar(100) ); Query OK, 0 rows affected (0.97 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable values('Adam'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.37 sec) mysql> insert into DemoTable values('Mike'); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.27 ...
Read MoreFetch random rows from a table with MySQL
For this, you can use a PREPARE statement. Let us first create a table −mysql> create table DemoTable( FirstName varchar(100), CountryName varchar(100) ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam', 'US'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Chris', 'AUS'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Robert', 'UK'); Query OK, 1 row affected (0.32 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+-----------+-------------+ | FirstName | ...
Read MoreCheck if a given year is leap year in PL/SQL
Here we will see how to check given year is leap year or not, using PL/SQL. In PL/SQL code, some group of commands are arranged within a block of related declaration of statements.The leap year checking algorithm is like below.AlgorithmisLeapYear(year): begin if year is divisible by 4 and not divisible by 100, then it is leap year else if the number is divisible by 400, then it is leap year else it is not leap year endExampleDECLARE year NUMBER := 2012; BEGIN IF MOD(year, 4)=0 ...
Read MoreHow to find repeated rows and display there count in a separate column with MySQL?
For this, use the GROUP BY HAVING clause. Let us first create a table −mysql> create table DemoTable( Name varchar(100), Age int ); Query OK, 0 rows affected (1.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 23); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('David', 21); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Chris', 23); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Chris', 21); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values('Mike', 25); Query OK, ...
Read MoreSelect with set order in MySQL
For this, you need to use IN() and after that FIELD() method. Let us first create a table −mysql> create table DemoTable( StudentId varchar(10), StudentName varchar(20) ) ; Query OK, 0 rows affected (4.11 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('10001', 'Adam'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable values('1010', 'Chris'); Query OK, 1 row affected (0.72 sec) mysql> insert into DemoTable values('1020', 'Bob'); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable values('1030', 'Carol'); Query OK, 1 row affected (0.47 sec) mysql> insert into ...
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