Let us first create a table −mysql> create table DemoTable    -> (    -> DueDate date    -> ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-11'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values('2019-04-19'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+------------+ | DueDate    | +------------+ | 2019-01-11 | | 2019-04-19 | +------------+ 2 rows in set (0.00 sec)Following is the query to display ... Read More

To find duplicate tuples, use GROUP BY HAVING clause. Let us first create a table −mysql> create table DemoTable    -> (    -> Id int,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(101, 'David'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values(101, 'Mike'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(100, 'Carol'); Query OK, 1 row affected (0.17 sec) ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> StudentName varchar(20),    -> StudentMarks int    -> ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 50); Query OK, 1 row affected (0.61 sec) mysql> insert into DemoTable values('David', 70); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable values('Chris', 80); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('David', 90); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> ... Read More

Yes, you can store double and date in VARCHAR. Let us first create a table −mysql> create table DemoTable    -> (    -> Amount varchar(20),    -> JoiningDate varchar(20)    -> ); Query OK, 0 rows affected (0.96 sec)Insert some records in the table using insert command. We are inserting varchar double and date values −mysql> insert into DemoTable values('150.50', 'Oct 10, 2019'); Query OK, 1 row affected (0.91 sec) mysql> insert into DemoTable values('173.45', 'Sept 11, 2018'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('173.90', 'Jan 01, 2017'); Query OK, 1 row affected (0.16 ... Read More

To drop a primary key, use ALTER at first to alter the table. With that, use DROP to drop the key as in the belowSyntaxalter table yourTableName drop primary key;Let us first create a table −mysql> create table DemoTable    -> (    -> StudentId int NOT NULL,    -> StudentName varchar(20),    -> StudentAge int,    -> primary key(StudentId)    -> ); Query OK, 0 rows affected (0.48 sec)Here is the query to check the description of table −mysql> desc DemoTable;This will produce the following output−+-------------+-------------+------+-----+---------+-------+ | Field       | Type        | Null | ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> Id int,    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, NULL); Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable values(NULL, 'David'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values(NULL, NULL); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select * from DemoTable;This will produce the following output−+------+-------+ |   Id | ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> Name varchar(20)    -> ); Query OK, 0 rows affected (0.49 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris Brown'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('Adam Smith'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('John Smith'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Carol Smith'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select * from DemoTable;This ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> BreakfastTime time    -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('7:30:45'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('8:00:30'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('7:55:00'); Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement −mysql> select * from DemoTable;This will produce the following output −+---------------+ | BreakfastTime | +---------------+ | 07:30:45      | | ... Read More

To get the database name, use the below given syntax −select database();Let us implement the above syntax in the stored procedure −mysql> delimiter // mysql> create procedure get_procedure_database_name()    -> begin    -> select concat('The database name=',database());    -> end    -> // Query OK, 0 rows affected (0.34 sec) mysql> delimiter ;Now you can call a stored procedure using CALL command −mysql> call get_procedure_database_name();This will produce the following output −+-----------------------------------------+ | concat('The database name=',database()) | +-----------------------------------------+ | The database name=web                   | +-----------------------------------------+ 1 row in set (0.05 sec) Query OK, 0 rows affected (0.08 sec)

Let us first create a table −mysql> create table DemoTable    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.59 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(40); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(60); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(45); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(85); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(78); Query OK, 1 row affected (0.10 sec)Display all records from the table ... Read More