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For this, use GROUP BY along with ORDER BY −select yourColumnName, count(*) as anyAliasName from yourTableName group by yourColumnName order by yourColumnName;Let us create a table −mysql> create table demo7 −> ( −> id int NOT NULL AUTO_INCREMENT, −> first_name varchar(50) −> , −> primary key(id) −> ); Query OK, 0 rows affected (1.22 sec)Insert some records into the table with the help of insert command −mysql> insert into demo7(first_name) values('John'); Query OK, 1 row affected (0.09 sec) mysql> insert into demo7(first_name) values('David'); Query OK, 1 row affected (0.22 sec) mysql> insert into demo7(first_name) values('John'); Query OK, 1 row affected ... Read More
To get rid of LOCK TABLES query, you need to use UNLOCK TABLES.Let us create a table −mysql> create table demo6 −> ( −> country_name varchar(100 −> ) −> ); Query OK, 0 rows affected (1.51 sec)Insert some records into the table with the help of insert command −mysql> insert into demo6 values('US'); Query OK, 1 row affected (0.11 sec) mysql> insert into demo6 values('UK'); Query OK, 1 row affected (0.08 sec) mysql> insert into demo6 values('AUS'); Query OK, 1 row affected (0.11 sec)Display records from the table using select statement −mysql> select *from demo6;This will produce the ... Read More
For this, you can use UNION ALL along with LIMIT concept. For our example, we will create three tables.Let us create the first table −mysql> create table demo3 −> ( −> value int −> ); Query OK, 0 rows affected (1.39 sec)Insert some records into the table with the help of insert command −mysql> insert into demo3 values(10); Query OK, 1 row affected (0.13 sec) mysql> insert into demo3 values(20); Query OK, 1 row affected (0.08 sec) mysql> insert into demo3 values(30); Query OK, 1 row affected (0.08 sec)Display records from the table using select statement −mysql> select ... Read More
Following is the syntax implementing multiple LIKE operators with ORDER BY −select *from yourTableName order by ( yourColumnName like '%yourValue1%' ) + ( yourColumnName like '%yourValue2%' ) + . . N desc;Let us create a table −mysql> create table demo2 −> ( −> id int not null auto_increment, −> name varchar(100), −> primary key(id) −> ); Query OK, 0 rows affected (1.53 sec)Insert some records into the table with the help of insert command −mysql> insert into demo2(name) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into demo2(name) values('David'); Query OK, 1 row affected (0.09 ... Read More
In order to get number located at 2 places before decimal point, you can use the concept of div.Let us create a table −mysql> create table demo1 −> ( −> value float −> ); Query OK, 0 rows affected (2.20 sec)Insert some records into the table with the help of insert command −mysql> insert into demo1 values(456.54); Query OK, 1 row affected (0.16 sec) mysql> insert into demo1 values(50.64); Query OK, 1 row affected (0.17 sec) mysql> insert into demo1 values(1000.78); Query OK, 1 row affected (0.13 sec)Display records from the table using select statement −mysql> select *from demo1;This will ... Read More
Suppose we have a picture consisting of black and white pixels, we have to find the number of black lonely pixels. Here the picture is represented by a 2D char array consisting of 'B' and 'W', for the black and white pixels respectively.A black lonely pixel is actually 'B' that located at a specific position where the same row and same column don't have any other black pixels.If the input is like −WWBWBWBWWOutput will be 3. Because all the three 'B's are black lonely pixels.To solve this, we will follow these steps −n := size of picturem := (if n ... Read More
Suppose we have a node in a binary search tree, we have to find the in-order successor of that node in the BST. If there is no in-order successor, return null. As we know that the successor of a node is the node with the smallest key greater than value of node.We will have direct access to the node but not to the root of the tree. Here each node will have a reference to its parent node. Below is the definition for Node −class Node { public int val; public Node left; public Node right; ... Read More
Suppose there is a ball in a maze with empty spaces and walls. Now the ball can go through empty paths by rolling any direction like up, down, left or right, but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction.We have to start position of ball, the destination and the maze, we have to find the shortest distance for the ball to stop at the destination. Here the distance is actually defined by the number of empty cells, that are covered by the ball (Excluding start position, including starting position). ... Read More
Suppose there is a ball in a maze with empty spaces and walls. Now the ball can go through empty paths by rolling any direction like up, down, left or right, but it won't stop rolling until hitting a wall. When the ball stops, it could choose the next direction.We have to start position of ball, the destination and the maze, we have to check whether the ball could stop at the destination. The maze is represented by one 2D array. Here 1 indicates the wall and 0 indicates the empty space. The borders of the maze are all walls. ... Read More
Suppose we have a binary array; we have to find the maximum number of consecutive 1s in this array if we can flip at most one 0.So, if the input is like [1, 0, 1, 1, 0], then the output will be 4 because if we flip the first zero will get the maximum number of consecutive 1s. After flipping, the maximum number of consecutive 1s is 4.To solve this, we will follow these steps −ret := 1, n := size of numsif not n is non-zero, then −return 0j := 0, zero := 0for initialize i := 0, when ... Read More