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Articles by Sravani S
Page 4 of 6
How can we fetch alternate even-numbered records from MySQL table?
To understand this concept we are using the data from table ‘Information’ as follows −mysql> Select * from Information; +----+---------+ | id | Name | +----+---------+ | 1 | Gaurav | | 2 | Ram | | 3 | Rahul | | 4 | Aarav | | 5 | Aryan | | 6 | Krishan | +----+---------+ 6 rows in set (0.00 sec)Now, the query below will fetch the alternate even-numbered records from the above table ‘Information’ −mysql> Select id,Name from information group by id having mod(id,2) = 0; +----+---------+ | id | Name | +----+---------+ | 2 | Ram | | 4 | Aarav | | 6 | Krishan | +----+---------+ 3 rows in set (0.00 sec)
Read MoreHow can we use MySQL SELECT without FROM clause?
FROM clause after SELECT shows the references to a table. But if there is no reference to any table then we can use SELECT without the FROM clause. In other words, we can say that SELECT can be used to retrieve rows computed without reference to any table. Consider the following statements −mysql> Select concat_ws(" ","Hello", "World"); +---------------------------------+ | concat_ws(" ","Hello", "World") | +---------------------------------+ | Hello World | +---------------------------------+ 1 row in set (0.00 sec) mysql> Set @var1=100; Query OK, 0 rows affected (0.00 sec) mysql> Select @var1; +-------+ | @var1 | +-------+ | 100 | +-------+ 1 row in set (0.00 sec)
Read MoreWhat are the different MySQL prompts we have on the command line?
As we know that after writing the first line of multiple-line queries, MySQL changes the prompt. The following table shows different MySQL prompts and it's meaning −PromptMeaning mysql>It means MySQL is ready for a new command. →It means that MySQL is waiting for the next line of multiple-line command. ‘>It means that MySQL is waiting for the next line, waiting for the completion of a string that began with a single quote. “>It means that MySQL is waiting for the next line, waiting for the completion of a string that began with a double quote. `>It means that MySQL is waiting ...
Read MoreCreate a MySQL stored procedure, which takes the name of the database as its parameter, to list the tables with detailed information in a particular database.
Suppose currently we are using a database named ‘query’ and it is having the following tables in it −mysql> Show tables in query; +-----------------+ | Tables_in_query | +-----------------+ | student_detail | | student_info | +-----------------+ 2 rows in set (0.00 sec)Now, following is a stored procedure, which will accept the name of the database as its parameter and give us the list of tables with detailed information −mysql> DELIMITER// mysql> CREATE procedure tb_list(db_name varchar(40)) -> BEGIN -> SET @z := CONCAT('Select * from information_schema.tables WHERE table_schema = ', ''', db_name, ...
Read MoreHow can we establish MySQL database by using MySQL binary at commandnprompt?
You can establish the MySQL database using the mysql binary at the command prompt. It can be understood with the help of the following example −ExampleWe can use following statements to connect to the MySQL server from the command prompt −[root@host]# mysql -u root -p Enter password:******This will give us the mysql> command prompt where we will be able to execute any SQL command. Following is the result of above command −The following code block shows the result of above code −Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 4 Server version: 5.7.20 MySQL ...
Read MoreHow MySQL reacts when we specify a CHARACTER SET binary attribute for a character string data type?
On specifying a CHARACTER SET binary attribute for a character string data type, MySQL creates that column as its subsequent binary string type. The conversions for CHAR, VARCHAR and BLOB data types take place as follows −CHAR would become BINARYVARCHAR would become VARBINARYTEXT would become BLOBThe above kind of conversion does not occur for ENUM and SET data type and they both are created as declared while creating the table.ExampleIn the example below we have created a table named ‘EMP’ with four columns all specified as CHARACTER SET binary as follows −mysql> Create table Emp(Name varchar(10) CHARACTER SET binary, Address ...
Read MoreIn MySQL, how can we use FROM_UNIXTIME() function with format string?
Suppose if we want the output of FROM_UNIXIME() function in a particular format then we can use date format string or time format string or both in it. Following is the example of using the format string in FROM_UNIXTIME() function −mysql> Select FROM_UNIXTIME(1555033470 '%Y %M %D')AS 'Formatted Output'; +------------------+ | Formatted Output | +------------------+ | 2019 April 12th | +------------------+ 1 row in set (0.00 sec)In the query above, it is using only date format string.mysql> Select FROM_UNIXTIME(1555033470 '%h:%i:%s')AS 'Formatted Output'; +------------------+ | Formatted Output | +------------------+ | 07:14:30 | +------------------+ 1 row in set (0.00 ...
Read MoreHow can we generate Strong numbers in Python?
To print Strong Numbers, let's first look at the definition of it. It is a number that is the sum of factorials of its own digits. For example, 145 is a Strong number. First, create a function to calculate factorial:def fact(num): def factorial(n): num = 1 while n >= 1: num = num * n n = n - 1 return numYou can print these numbers by running the following code:def factorial(n): num ...
Read MoreHow to create a triangle using Python for loop?
There are multiple variations of generating triangle using numbers in Python. Let's look at the 2 simplest forms:for i in range(5): for j in range(i + 1): print(j + 1, end="") print("")This will give the output:1 12 123 1234 12345You can also print numbers continuously using:start = 1 for i in range(5): for j in range(i + 1): print(start, end=" ") start += 1 print("")This will give the output:1 2 3 4 5 6 7 8 9 10 11 12 13 14 15You can also print these numbers in reverse using:start = 15 for i in range(5): for j in range(i + 1): print(start, end=" ") start -= 1 print("")This will give the output:15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Read MoreHow can we do Python operator overloading with multiple operands?
You can do Python operator overloading with multiple operands just like you would do it for binary operators. For example, if you want to overload the + operator for a class, you'd do the following −Exampleclass Complex(object): def __init__(self, real, imag): self.real = real self.imag = imag def __add__(self, other): real = self.real + other.real imag = self.imag + other.imag return Complex(real, imag) def display(self): print(str(self.real) + " + " + str(self.imag) + "i") a = Complex(10, 5) b = Complex(5, 10) c = Complex(2, 2) d = a + b + c d.display()OutputThis will give the output −17 + 17i
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