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Found 6702 Articles for Database
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
73 Views
You can use SUBSTRING() along with UPDATE command to delete last 4 letters. Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentSubject varchar(100) ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentSubject) values('Introduction to Java'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(StudentSubject) values('Introduction to C'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentSubject) values('Introduction to C++'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(StudentSubject) values('Spring And Hibernate'); ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
2K+ Views
There is no double equal sign concept. It can be used to compare two values. If you use double equal sign(==) in MySQL, you will get an error message.Let us verify the concept is true or not. Declare a variable −mysql> set @Number=10; Query OK, 0 rows affected (0.00 sec)Now, compare the above variable value with 10. If both the values are same then the result will be 1 otherwise 0.Using double equal sign −mysql> select 10==@Number;This will produce the following output i.e. an error −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual ... Read More
![Krantik Chavan](https://www.tutorialspoint.com/assets/profiles/13545/profile/60_126883-1512724834.jpg)
186 Views
Yes, you can use SUM() with IF() in MySQL. Let us first create a demo table:mysql> create table DemoTable ( Value int, Value2 int ); Query OK, 0 rows affected (0.51 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable values(100, 400); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(100, 400); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(400, 100); Query OK, 1 row affected (0.14 sec)Following is the query to display records from the table using select command:mysql> select *from DemoTable;This ... Read More
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
334 Views
You can use aggregate function SUM() for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstValue int, SecondValue int, ThirdValue int ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(10, 20, 30); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(60, 50, 40); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(80, 90, 100); Query OK, 1 row affected ... Read More
![Krantik Chavan](https://www.tutorialspoint.com/assets/profiles/13545/profile/60_126883-1512724834.jpg)
138 Views
In MySQL, COUNT() will display the number of rows. DISTINCT is used to ignore duplicate rows and get the count of only unique rows.Let us first create a table:mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(10) ); Query OK, 0 rows affected (0.47 sec)Following is the query to insert some records in the table using insert command:mysql> insert into DemoTable(FirstName) values('Larry'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(FirstName) values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable(FirstName) values('Sam'); Query OK, 1 row affected (0.13 sec) ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
165 Views
You can use LIKE operator with wildcards to select the records where last value in a string = x, for example ‘10’, ‘15’, etc.Let us first create a table −mysql> create table DemoTable ( ClientId varchar(20) ); Query OK, 0 rows affected (0.68 sec)Insert records in the table using insert command −mysql> insert into DemoTable values('CLI-101'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('CLI-110'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('CLI-201'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('CLI-210'); Query OK, 1 row affected (0.13 sec) ... Read More
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
124 Views
You can use modify command for this. Let us first us create a table.mysql> create table DemoTable ( StudentId varchar(200) not null, StudentName varchar(20), StudentAge int, StudentAddress varchar(20), StudentCountryName varchar(20) ); Query OK, 0 rows affected (0.73 sec)Now check the description of table.mysql> desc DemoTable;This will produce the following output −+--------------------+--------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------------------+--------------+------+-----+---------+-------+ | StudentId | varchar(200) | NO | | NULL | ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
486 Views
Use the concept of IFNULL() method to treat NULL as 0. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Value1 int, Value2 int ); Query OK, 0 rows affected (0.64 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Value1, Value2) values(10, 20); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Value1, Value2) values(null, null); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable(Value1, Value2) values(40, null); Query OK, 1 row affected (0.18 sec)Following is the query to display all ... Read More
![Samual Sam](https://www.tutorialspoint.com/assets/profiles/13514/profile/60_83486-1512649303.jpg)
441 Views
You can use the concept of IFNULL() for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(100) DEFAULT 'Larry', Age int DEFAULT NULL ); Query OK, 0 rows affected (0.73 sec)Insert records in the table using insert command −mysql> insert into DemoTable(Name, Age) values('John', 23); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable(Name) values('David'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Age) values(24); Query OK, 1 row ... Read More
![karthikeya Boyini](https://www.tutorialspoint.com/assets/profiles/13518/profile/60_31598-1537784993.jpg)
80 Views
You can use update along with lower() function for this. Let us first create a table −mysql> create table DemoTable ( Id varchar(100), StudentFirstName varchar(20), StudentLastName varchar(20), StudentCountryName varchar(10) ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('STU-101', 'John', 'Smith', 'US'); Query OK, 1 row affected (0.59 sec) mysql> insert into DemoTable values('STU-102', 'John', 'Doe', 'UK'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('STU-103', 'David', 'Miller', 'AUS'); Query OK, 1 row affected (0.19 sec)Following is the query to display all ... Read More