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We can use CONCAT() function to combine the values of two or more columns. In this case, the arguments of the CONCAT() functions would be the name of the columns. For example, suppose we have a table named ‘Student’ and we want the name and address of the student collectively in one column then the following query can be written −mysql> Select Id, Name, Address, CONCAT(ID, ', ', Name, ', ', Address)AS 'ID, Name, Address' from Student; +------+---------+---------+--------------------+ | Id | Name | Address | ID, Name, Address | +------+---------+---------+--------------------+ | 1 | Gaurav | Delhi ... Read More
Suppose from the table ‘Student’ we want to concatenate the values of columns, ‘Name’, ‘Address’ and ‘Columns’, based on the condition that is also a concatenation of values from columns, ’Name’, ‘Subject’, provided in WHERE clause with the help of CONCAT() function. We can use the following query to give the output −mysql> Select CONCAT(Name, ' ', 'Resident of', ' ', Address, ' ', 'is', ' ', 'Studying', ' ', Subject)AS 'Detail of Student' from Student WHERE CONCAT(Name, Subject) = "AaravHistory"; +----------------------------------------------+ | Detail of Student | ... Read More
Python deletes unneeded objects (built-in types or class instances) automatically to free the memory space. The process by which Python periodically reclaims blocks of memory that no longer are in use is termed Garbage Collection.Python's garbage collector runs during program execution and is triggered when an object's reference count reaches zero. An object's reference count changes as the number of aliases that point to it changes.An object's reference count increases when it is assigned a new name or placed in a container (list, tuple, or dictionary). The object's reference count decreases when it's deleted with del, its reference is reassigned, or ... Read More
MySQL CAST can handle overflow occurs during numerical expression assessment. Suppose if numeric expression evaluation produces overflow then MySQL reflects an error message. Now to handle this overflow we can change that numeric value to UNSIGNED with the help of CAST.For example on adding 1 to BIGINT maximum value, MySQL produce an error due to overflow as follows −mysql> Select 9223372036854775807 + 1; ERROR 1690 (22003): BIGINT value is out of range in '(9223372036854775807+1)'Now, with the help of CAST, MySQL handles this kind of overflow as follows:mysql> Select CAST(9223372036854775807 AS UNSIGNED) +1; +------------------------------------------+ | CAST(9223372036854775807 AS UNSIGNED) +1 | +------------------------------------------+ | 9223372036854775808 | +------------------------------------------+ 1 row in set (0.07 sec)
MySQL exact-value arithmetic can handle overflow occurs during numerical expression assessment because overflow occurs depends on the range of the operands. The values used in arithmetic expressions changed to other data type can put away the overflow.For example, after converting the BIGINT Maximum value to DECIMAL while adding 1 to it can handle the overflow as follows −mysql> Select 9223372036854775807.0 + 1; +---------------------------+ | 9223372036854775807.0 + 1 | +---------------------------+ | 9223372036854775808.0 | +---------------------------+ 1 row in set (0.01 sec)
In case of enabled SQL strict mode, subtraction between integers value in which one is of UNSIGNED type will produce an unsigned result by default. But MySQL produces an error if the result is a negative one. It can be observed with the following example −mysql> SET sql_mode = ''; Query OK, 0 rows affected (0.00 sec) mysql> Select CAST(0 AS UNSIGNED) -1; ERROR 1690 (22003): BIGINT UNSIGNED value is out of range in '(cast(0 as unsigned) - 1)'The error after the query above shows that it is an overflow after numeric arithmetic expression.Now, it can be handled with ... Read More
The class statement creates a new class definition. The name of the class immediately follows the keyword class followed by a colon as follows −class ClassName: 'Optional class documentation string' class_suiteThe class has a documentation string, which can be accessed via ClassName.__doc__.The class_suite consists of all the component statements defining class members, data attributes and functions.ExampleFollowing is the example of a simple Python class −class Employee: 'Common base class for all employees' empCount = 0 def __init__(self, name, salary): self.name = name self.salary = salary Employee.empCount += 1 def displayCount(self): ... Read More
With the help of the following command we can force MySQL out of TRADITIONAL mode −mysql> Set SQL_MODE =''; Query OK, 0 rows affected (0.00 sec)
The HTML5 checkValidity() works in Google Chrome and Opera as well. This works as well: .valid { color: #0B7866; } .invalid { color: #0B6877; } function check(input) { var out = document.getElementById('result'); if (input.validity) { if (input.validity.valid === true) { out.innerHTML = "" + input.id + " valid"; } else { out.innerHTML = "" + input.id + " not valid"; } } console.log(input.checkValidity()); }; Minimum:
Last_Insert_Id() MySQL function is used to find out which sequence number was assigned recently by AUTO_INCREMENT.Examplemysql> Create table Employee(Id INT PRIMARY KEY NOT NULL AUTO_INCREMENT, Name Varchar(5)); Query OK, 0 rows affected (0.13 sec) mysql> Insert into Employee(Name) Values('Harvinder'); Query OK, 1 row affected (0.06 sec) mysql> Insert into Employee(Name) Values('Suresh'); Query OK, 1 row affected (0.07 sec) mysql> Select* from Employee; +----+---------+ | Id | Name | +----+---------+ | 1 |Harvinder| | 2 | Suresh | +----+---------+ 2 rows in set (0.00 sec) mysql> Select Last_insert_id(); +------------------+ | Last_insert_id() | +------------------+ | 2 | +------------------+ 1 row in set (0.00 sec)