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Articles by George John
Page 61 of 79
MySQL query to list all the items in a group in one record?
You can use GROUP_CONCAT() function to list all the items in a group in one record. Let us first create a table −mysql> create table DemoTable ( ProductId int, ProductName varchar(40), ProductCategory varchar(40) ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100, 'Product-1', '1Product'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(101, 'Product-2', '2Product'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(100, 'Product-1', '3Product'); Query OK, 1 row affected (0.14 sec)Following is the query to display all ...
Read MoreStored procedure using variable in LIMIT expression?
Let us firs create a tablemysql> create table LimitWithStoredProcedure -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(10) -> ); Query OK, 0 rows affected (0.47 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into LimitWithStoredProcedure(Name) values('John'); Query OK, 1 row affected (0.15 sec) mysql> insert into LimitWithStoredProcedure(Name) values('Chris'); Query OK, 1 row affected (0.15 sec) mysql> insert into LimitWithStoredProcedure(Name) values('Maxwell'); Query OK, 1 row affected (0.28 sec) mysql> insert into LimitWithStoredProcedure(Name) values('Bob'); Query OK, 1 row affected (0.24 sec) mysql> insert into LimitWithStoredProcedure(Name) values('David'); Query ...
Read MoreQuery MySQL database to echo highest auto incremented number?
Let us first create a table with Id as auto_increment −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserName varchar(20) ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName) values('John'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(UserName) values('Larry'); Query OK, 1 row affected (0.35 sec) mysql> insert into DemoTable(UserName) values('Chris'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(UserName) values('Bob'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(UserName) values('Carol'); Query OK, 1 row affected ...
Read MoreHow to revert rows to default column value in MySQL?
To revert rows to default column value, let us first create a demo tablemysql> create table defaultDemo -> ( -> Id int -> ); Query OK, 0 rows affected (0.48 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into defaultDemo values(10); Query OK, 1 row affected (0.25 sec) mysql> insert into defaultDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into defaultDemo values(30); Query OK, 1 row affected (0.14 sec) mysql> insert into defaultDemo values(40); Query OK, 1 row affected (0.11 sec) mysql> insert into defaultDemo values(80); Query OK, ...
Read MoreWhat are copy elision and return value optimization in C++?
The Copy Elision is also known as the Copy Omission. This is one of the compiler optimization technique. It avoids the unnecessary copying of objects. Almost any current compiler uses this Copy Elision technique.Let us see how it works by the help of one example code.Example Code#include using namespace std; class MyClass { public: MyClass(const char* str = "\0") { //default constructor cout
Read More8085 Program to perform selection sort in ascending order
Now let us see a program of Intel 8085 Microprocessor. In this program we will see how to sort a sequence of numbers using selection sort.Problem Statement:Write 8085 Assembly language program to sort a given sequence using selection sort in ascending order. The numbers are stored at 8001H onwards. 8000H is holding the block size.Discussion:In the selection sorting technique, we will choose the minimum or the maximum term from a set of numbers. In this case we are considering the sorting in ascending order, so we are choosing the minimum number. By taking the minimum number, we are swapping it ...
Read MoreHow to count number of specific symbols in a row in MySQL?
You can use LENGTH() to count number of specific symbols in a row. Let us first create a table −mysql> create table DemoTable ( Value varchar(200) ); Query OK, 0 rows affected (0.54 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('?1234?6789?5656?324?'); Query OK, 1 row affected (0.17 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----------------------+ | Value | +----------------------+ | ?1234?6789?5656?324? | ...
Read MoreHow to display the bit(1) fields in MySQL?
Let us first create a table. Here, our columns is of type bit(1) −mysql> create table DemoTable ( isCaptured bit(1) ); Query OK, 0 rows affected (1.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.47 sec) mysql> insert into DemoTable values(1); Query OK, 1 row affected (0.29 sec)Following is the query to display all records from the table using select statement −mysql> select ...
Read MoreExtract the user ID from the username only in MySQL?
To extract the User ID only from MySQL, you can use SUBSTRING_INDEX(), which extracts the part of a string from the Username to get the User ID. Let us first display the user −mysql> SELECT USER();This will produce the following output −+----------------+ | USER() | +----------------+ | root@localhost | +----------------+ 1 row in set (0.00 sec)Let us now extract the UserID only −mysql> SELECT SUBSTRING_INDEX(USER(), '@', 1);This will produce the following output −+-------------------------------+ | SUBSTRING_INDEX(USER(), '@', 1) | +-------------------------------+ | root ...
Read MoreWhy does the order in which libraries are linked sometimes cause errors in GCC?
Basically this kind of errors are originated from the linker in the compilation phase. The default behavior of a linker is to take the code from archive libraries when the current program needs it.To work properly the libraries must be present in order. We can say that it must be there in the form “caller before callees”. This problem can be solved by choosing non-default behavior using flags, but in this process the linking may take larger time. Otherwise it can be solved by ordering the libraries correctly. Loaders and tsort these two can help to rearrange and correct the ...
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