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Articles by Rishi Rathor
Page 7 of 10
How to use compound INTERVAL unit in MySQL?
Compound INTERVAL unit keywords are made up of two keywords and separated by an underscore (_). For using them in MySQL the unit values must be enclosed in single quotes and separated by space.Example − Following query will add 2 years and 2 months in the date value.mysql> Select timestamp('2017-10-22 04:05:36' + INTERVAL '2 2' year_month) AS'Date After 2 Years and 2 Months'; +---------------------------------+ | Date After 2 Years and 2 Months | +---------------------------------+ | 2019-12-22 04:05:36 | +---------------------------------+ 1 row in set (0.00 sec)
Read MoreWhy it shows 0 instead of empty string whenever I insert an empty string into a MySQL column which is declared as NOT NULL?
It is because inserting an empty string means that we are inserting some value and not NULL. The empty string apparently maps to zero as an integer. In other words, we can say that by inserting empty string we are providing a value to MySQL that has integer representation as INT 0. Consider the following example in which we inserted an empty string and it mapped to 0 by MySQL.mysql> create table test(id int NOT NULL, Name Varchar(10)); Query OK, 0 rows affected (0.19 sec) mysql> Insert into test(id, name) values('1', 'Gaurav'), ('0', 'Rahul'), ('', 'Aarav'); Query OK, 3 ...
Read MoreCan a local variable's memory be accessed outside its scope in C/C++?
Let us look at an example where you MIGHT be able to access a local variable's memory outside its scope.Example#include int* foo() { int x = 3; return &x; } int main() { int* address = foo(); cout
Read MoreHow to use together the date and time format characters in MySQL DATE_FORMAT() function?
We can use both the format characters together in DATE_FORMAT() function. The following example will clarify this −mysql> SELECT DATE_FORMAT(NOW(), 'The time is %a %h:%i:%s:%f %p'); +-----------------------------------------------------+ | DATE_FORMAT(NOW(), 'The time is %a %h:%i:%s:%f %p') | +-----------------------------------------------------+ | The time is Sun 06:35:06:000000 AM | +-----------------------------------------------------+ 1 row in set (0.00 sec)Above query is using date format character ‘%a’ along with other time format characters.Following is another example in which both format characters are used together −mysql> SELECT DATE_FORMAT(NOW(), 'The date & time is %a %D %M %Y %h:%i:%s:%f %p'); ...
Read MoreHow can we allow MySQL to store invalid dates?
After enabling the SQL MODE to ALLOW_INVALID_DATES, MySQL will also be able to store invalid dates in the table. The example is given below to understand it −mysql> Insert into order1234(ProductName, Quantity, Orderdate) values('B',500,'2015-11-31'); Query OK, 1 row affected (0.06 sec) mysql> Select * from order1234; +-------------+----------+--------------+ | ProductName | Quantity | OrderDate | +-------------+----------+--------------+ | A | 500 | 0000-00-00 | | B | 500 | 2015-11-31 | +-------------+----------+--------------+ 2 rows in set (0.00 sec)We can see MySQL also inserts the invalid date in a table.
Read MoreMySQL alias for SELECT * columns?
MySQL alias cannot be used with *. However, it can be used for individual column. The syntax is as follows −select anyaliasName.yourColumnName1 as anyaliasName1, anyaliasName.yourColumnName2 as anyaliasName2, anyaliasName.yourColumnName3 as anyaliasName3, anyaliasName.yourColumnName4 as anyaliasName4, . . . . N from yourTableName as anyaliasName;MySQL alias is a variable of table that can be used to access the column name of that particular table. To understand the above syntax, let us create a table.The query to create a table is as follows −mysql> create table TableAliasDemo −> ( −> Id int, −> Name varchar(100), −> Age int −> ...
Read MoreEquaivalent of Oracle concatenation operator in MySQL?
The concat operator can be used in ORACLE. MySQL use concat() function to perform concatenation.To understand the concat() function, let us create a table. The query to create a table is as follows −mysql> create table ConcatenationDemo −> ( −> Id int, −> Name varchar(100) −> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into ConcatenationDemo values(100, 'John'); Query OK, 1 row affected (0.19 sec) mysql> insert into ConcatenationDemo values(101, 'Sam'); Query ...
Read More8085 Executing the program and checking result
In this section we will see how to use 8085 to write a program in 8085 kit. We will also see how to debug the program and check the result after successful execution. Let us see a typical keypad structure of 8085 kit. (This keyboard pattern may vary indifferent kits of different manufacturers)The following table will show the functionalities of different control keys. There are 16alphanumeric keys (0-9, A-F) to provide data and address −KeysFunctionalitiesRESETReset the systemVCT INTVector Interrupt. It generates hardware interruptRST 7.5 via keypadSHIFTProvides second level commands to all keysGOExecute the programSIExecute in Single Step ModeEXREGExamine Register. It allows ...
Read More8085 Program to find the smallest number
In this program we will see how to find the smallest number from a block of bytes using 8085.Problem StatementWrite 8085 Assembly language program to find the smallest number from a block of bytes.DiscussionIn this program the data are stored at location 8001H onwards. The 8000H is containing the size of the block. After executing this program, it will return the smallest number and store it at location 9000H.Logic is simple, we are taking the first number at register B to start the job. In each iteration we are getting the number from memory and storing it into register A. ...
Read More8085 Program to convert an 8-bit binary to BCD
In this program we will see how to convert binary numbers to its BCD equivalent.Problem StatementA binary number is store dat location 800H. Convert the number into its BCD equivalent and store it to the memory location 8050H.DiscussionHere we are taking a number from the memory, and initializing it as a counter. Now in each step of this counter we are incrementing the number by 1, and adjust the decimal value. By this process we are finding the BCD value of binary number or hexadecimal number.We can use INR instruction to increment the counter in this case but this instruction ...
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