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Found 6702 Articles for Database
679 Views
Let us first create a table −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserFirstName varchar(20), UserLastName varchar(20), UserAge int, UserCountryName varchar(20) ); Query OK, 0 rows affected (0.27 sec)Now check the description of table.mysql> desc DemoTable;This will produce the following output −+-----------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +-----------------+-------------+------+-----+---------+----------------+ | UserId | int(11) | NO | PRI ... Read More
105 Views
Use HAVING to find all columns where the column name length is greater than 5. This will produce the following output −+-------------------+-------------------------+ | TABLE_NAME | COLUMN_NAME | +-------------------+-------------------------+ | DemoTable | UserId | | DemoTable | EndDate | | DemoTable | StartDate | | DemoTable | StudentFavouriteSubject | | DemoTable ... Read More
3K+ Views
Following is the query to create a stored procedure that creates a table. Here, we are creating a table with three columns, one of them is Id −mysql> DELIMITER // mysql> CREATE PROCEDURE Stored_Procedure_CreatingTable() BEGIN create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserFirstName varchar(20), UserLastName varchar(20) ); END; // Query OK, 0 rows affected (0.16 sec) mysql> DELIMITER ;Now you can call stored procedure with the help of CALL command −mysql> call Stored_Procedure_CreatingTable(); ... Read More
340 Views
To count common elements, use COUNT() and GROUP BY. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Number int ); Query OK, 0 rows affected (0.20 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Number) values(10); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable(Number) values(20); Query OK, 1 row affected (0.04 sec) mysql> insert into DemoTable(Number) values(20); Query OK, 1 row affected (0.04 sec) mysql> insert into DemoTable(Number) values(30); Query OK, 1 row affected (0.04 sec) ... Read More
565 Views
To count presence of a NOT NULL value, use aggregate function COUNT(yourColumnName). Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, NumberOfQuestion int, NumberOfSolution int ); Query OK, 0 rows affected (0.20 sec)Insert some records in the table using insert command. Here, some of the values are NULL −mysql> insert into DemoTable(NumberOfQuestion, NumberOfSolution) values(20, 10); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable(NumberOfQuestion, NumberOfSolution) values(20, 2); Query OK, 1 row affected (0.04 sec) mysql> insert into DemoTable(NumberOfQuestion, NumberOfSolution) values(20, NULL); Query ... Read More
424 Views
For this, use subquery along with HAVING clause. Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentLastName varchar(20) ); Query OK, 0 rows affected (0.27 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('John', 'Smith'); Query OK, 1 row affected (0.04 sec) mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('Carol', 'Taylor'); Query OK, 1 row affected (0.04 sec) mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('John', 'Doe'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(StudentFirstName, ... Read More
78 Views
Use CHAR_LENGTH(yourColumnName) at the time of table creation. Let us first see an example and create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Title varchar(200), `Number_of_characters` int as (char_length(Title)) ); Query OK, 0 rows affected (0.18 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Title) values('Introduction To MySQL'); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable(Title) values('Introduction To Java'); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable(Title) values('Introduction To MongoDB'); Query OK, 1 row affected (0.04 ... Read More
396 Views
Use DATE_FORMAT for this. Let us first create a table −mysql> create table DemoTable ( ShippingDate varchar(200) ); Query OK, 0 rows affected (0.25 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('04:58 PM 10/31/2018'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('02:30 AM 01/01/2019'); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable values('12:01 AM 05/03/2019'); Query OK, 1 row affected (0.06 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+---------------------+ | ... Read More
75 Views
Use aggregate function MIN() along with GROUP BY for this. Here, we will display the minimum ID for NumberOfProduct . Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, NumberOfProduct int ); Query OK, 0 rows affected (0.19 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(NumberOfProduct) values(40); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(NumberOfProduct) values(40); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable(NumberOfProduct) values(60); Query OK, 1 row affected (0.07 sec) mysql> ... Read More
517 Views
You can use GROUP_CONCAT() function from MySQL to display result as a comma separated list. Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.26 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.07 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.06 sec) mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.07 sec) mysql> ... Read More