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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to update a MySQL table by swapping two column values?
To swap two values in a column, use CASE WHEN statement. Let us first create a table −mysql> create table DemoTable1382 -> ( -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1382 values('John'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1382 values('Chris'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1382 values('Adam'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1382 values('Bob'); Query OK, 1 row affected (0.17 sec)Display all records from the table using ...
Read MoreHow to get the maximum value from a column with alphanumeric strings beginning with specific characters in MYSQL?
For maximum value, use MAX() along with CAST() for conversion. Since we want maximum value from string-numbers beginning with specific characters, use RLIKE. Let us first create a table −mysql> create table DemoTable1381 -> ( -> DepartmentId varchar(40) -> ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1381 values('IT794'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1381 values('AT1034'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable1381 values('IT967'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1381 values('IT874'); Query ...
Read MoreMySQL UNION SELECT and IN clause in a single query
Let us first create a table −mysql> create table DemoTable1 -> ( -> StudentId int, -> StudentName varchar(20) -> ); Query OK, 0 rows affected (1.24 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(210, 'Adam'); Query OK, 1 row affected (0.11 sec)Display all records from the table using select statement −mysql> select * from DemoTable1;This will produce the following output −+-----------+-------------+ | StudentId | StudentName | +-----------+-------------+ | 210 | Adam | +-----------+-------------+ 1 row in set (0.00 sec)Here is the query to create ...
Read MoreHow can I view cascades in MySQL?
To view cascades, use SHOW CREATE TABLE in MySQL. Let us first create a table −mysql> create table DemoTable1378 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> EmployeeId varchar(20), -> EmployeeFirstName varchar(20), -> EmployeeLastName varchar(20), -> EmployeeCountryName varchar(40), -> EmployeeAge int, -> EmployeeSalary int, -> UNIQUE(EmployeeFirstName, EmployeeSalary), -> INDEX First_Last_NameIndex(EmployeeFirstName, EmployeeLastName) -> ); Query OK, 0 rows affected (0.93 sec)Let us now view cascades in MySQL −mysql> show create table DemoTable1378;This will produce the following output −+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table ...
Read MoreHow to add a year and two days to a date with a single MySQL query?
For this, use INTERVAL in MySQL. Let us first create a table −mysql> create table DemoTable1376 -> ( -> AdmissionDate date -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1376 values('2018-01-21'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1376 values('2017-12-01'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1376 values('2018-11-02'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1376 values('2019-03-14'); Query OK, 1 row affected (0.17 sec)Display all records from the table using select statement−mysql> select * from ...
Read MoreHow to use count with CASE condition in a MySQL query?
Use CASE WHEN for this in MySQL and set CASE condition inside the COUNT() method to count. Let us first create a table −mysql> create table DemoTable1374 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20), -> Score int -> ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1374(Name, Score) values('Chris', 45); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1374(Name, Score) values('David', 78); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1374(Name, Score) values('Bob', 45); ...
Read MoreUpdate a MySQL column with JSON format?
To display records like JSON format, use MySQL concat(). Let us first create a table −mysql> create table DemoTable1373 -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentDetails text -> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. Here, we haven’t inserted anything −mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1373 values(); Query OK, 1 row affected (0.18 sec)Display all records from the table using ...
Read MoreSubtracting a number from a single MySQL column value?
For this, just update the table and subtract. Let us first create a table −mysql> create table DemoTable1372 -> ( -> Value int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1372 values(500); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1372 values(100); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable1372 values(900); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1372 values(1000); Query OK, 1 row affected (0.32 sec)Display all records from the table using select statement −mysql> ...
Read MoreGet the sum only from specific cells in MySQL?
For only specific cells, set a condition with WHERE and use aggregate function SUM() to add. Let us first create a table −mysql> create table DemoTable1370 -> ( -> StudentName varchar(20), -> Marks int -> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1370 values('Adam Smith', 56); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable1370 values('Chris Brown', 67); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1370 values('Adam Smith', 69); Query OK, 1 row affected (0.20 sec) mysql> insert into ...
Read MoreLearn English Easy in 2020: Everything You Should Know About Learning English
English is the most common language that we ever come across in our daily lives; be it in media, entertainment, education, profession, travel, and other aspects. It means with good knowledge of English; we can lead our lives better and achieve much more than we do without it.Many of us who fear English would have included learning English in our new year resolutions many times. But, we often neglect to learn English as time passes due to plenty of reasons −Lack of timeFear of being laughed at for speaking wrong EnglishUnaware of the importance of EnglishWell, as career guidance experts ...
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