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Articles by Smita Kapse
Page 37 of 39
How to sort more than one column at a time in MySQL?
To sort more than one column at a time, you can use ORDER BY clause. Following is the syntax −select yourColumnName1, yourColumnName2, yourColumnName3 from yourTableName order by yourColumnName2, yourColumnName3;Let us first create a table −mysql> create table doubleSortDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100), -> StudentCountryName varchar(10) -> ); Query OK, 0 rows affected (0.71 sec)Following is the query to insert records in the table using insert command −mysql> insert into doubleSortDemo(StudentName, StudentCountryName) values('John', 'AUS'); Query OK, 1 row affected (0.21 sec) mysql> insert into doubleSortDemo(StudentName, StudentCountryName) values('Sam', ...
Read MoreResolve MySQL ERROR 1064 (42000): You have an error in your syntax?
This error occurs if let’s say you used var_char instead of varchar type. To remove this type of error, use, for example, varchar(100) instead of var_char(100).Let us now see how this error occurs −mysql> create table removeErrorDemo -> ( -> StudentId int, -> StudentName var_char(50) -> );The following is the output displaying the error −ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'var_char(50) )' at line 4Now let us remove the error. Here is the query ...
Read MoreMySQL select only duplicate records from database and display the count as well?
To select only duplicate records from database and display the count, use HAVING along with aggregate function count(). Let us first create a table −mysql> create table duplicateRecords -> ( -> ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> ClientName varchar(20) -> ); Query OK, 0 rows affected (0.49 sec)Following is the query to insert records in the table using insert command −mysql> insert into duplicateRecords(ClientName) values('John'); Query OK, 1 row affected (0.16 sec) mysql> insert into duplicateRecords(ClientName) values('Carol'); Query OK, 1 row affected (0.17 sec) mysql> insert into duplicateRecords(ClientName) values('John'); Query OK, 1 row affected ...
Read MoreCan we GROUP BY one column and select all data in MySQL?
Yes, you can use group_concat() for this. Let us first create a table −mysql> create table groupByOneSelectAll -> ( -> StudentDetails varchar(100), -> StudentName varchar(100) -> ); Query OK, 0 rows affected (0.91 sec)Following is the query to insert some records in the table using insert command −mysql> insert into groupByOneSelectAll values('StudentFirstName', 'John'); Query OK, 1 row affected (0.14 sec) mysql> insert into groupByOneSelectAll values('StudentFirstName', 'Chris'); Query OK, 1 row affected (0.21 sec) mysql> insert into groupByOneSelectAll values('StudentFirstName', 'Robert'); Query OK, 1 row affected (0.65 sec) mysql> insert into groupByOneSelectAll values('StudentFirstName', 'Bob'); Query ...
Read MoreWhy C++ does not have a virtual constructor?
The virtual mechanism works only when we have a base class pointer to a derived class object.In C++, constructor cannot be virtual, because when constructor of a class is executed there is no virtual table in the memory, means no virtual pointer defined yet. So, the constructor should always be non-virtual.But virtual destructor is possible. Here is an exampleExample#include using namespace std; class b { public: b() { cout
Read MoreSelect results from the middle of a sorted list in MySQL?
To select results from the middle of a sorted list, use ORDER BY clause along with LIMIT.Let us first create a table. Following is the query −mysql> create table sortedListDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100) -> ); Query OK, 0 rows affected (0.46 sec)Following is the query to insert some records in the table using insert command −mysql> insert into sortedListDemo(StudentName) values('John'); Query OK, 1 row affected (0.62 sec) mysql> insert into sortedListDemo(StudentName) values('Sam'); Query OK, 1 row affected (0.18 sec) mysql> insert into sortedListDemo(StudentName) values('Adam'); ...
Read MoreC++ Program to Implement Disjoint Set Data Structure
Disjoint set is basically as group of sets where no item can be in more than one set. It supports union and find operation on subsets.Find(): It is used to find in which subset a particular element is in and returns the representative of that particular set.Union(): It merges two different subsets into a single subset and representative of one set becomes representative of other.Functions and pseudocodesBegin Assume k is the element makeset(k): k.parent = k. Find(x): If k.parent == k return k. else return Find(k.parent) Union ...
Read MoreC++ Program to Implement Gauss Seidel Method
Gauss Seidel method is used to solve linear system of equations in iterative method. This is a C++ Program to Implement Gauss Seidel Method.AlgorithmBegin Take the dimensions of the matrix p and its elements as input. Take the initials values of x and no of iteration q as input. While q>0 Make a for loop i = 0 to p-1 initialize n[i] = (b[i] / a[i][i]). Make a for loop i = 0 to p-1 If (j == ...
Read MoreC++ Program to Perform Optimal Paranthesization Using Dynamic Programming
This is a C++ program to perform Optimal Paranthesization using Dynamic Programming.AlgorithmBegin Take the length n and dimension of matrix as input. MatrixChain() to find out minimum multiplications: Arguments: a[i][j]=Minimum number of scalar multiplications needed to compute the matrix A[i]A[i+1]...A[j] = A[i..j] where dimension of A[i] is p[i-1] x p[i]. a[i][j] means cost is zero when multiplying one matrix. L is chain length. m = cost / scalar multiplications. Body of the function: for i = ...
Read MoreHow to use substring () in Android textview?
This example demonstrate about How to use substring () in Android textview.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. In the above code, we have taken name as Edit text, when user click on button it will take data and return substring value.Step 3 − Add the following code to src/MainActivity.javapackage com.example.myapplication; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView; public ...
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