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Articles by George John
Page 60 of 79
MySQL update a column with an int based on order?
The syntax is as follows to update a column with an int based on orderset @yourVariableName=0; update yourTableName set yourColumnName=(@yourVariableName:=@yourVariableName+1) order by yourColumnName ASC;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table updateColumnDemo -> ( -> Id int, -> OrderCountryName varchar(100), -> OrderAmount int -> ); Query OK, 0 rows affected (1.76 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into updateColumnDemo(Id, OrderCountryName) values(10, 'US'); Query OK, 1 row affected (0.46 sec) mysql> insert into updateColumnDemo(Id, OrderCountryName) ...
Read More8086 program to find Square Root of a number
In this program we will see how to find the square root of a number.Problem StatementWrite 8086 Assembly language program to find the square root of a number. The number is stored at memory offset 500. Finally store the result at memory offset 600.DiscussionTo find the square root here at first we are clearing the counter register. In each iteration we are increasing BX register by 2. At first we need BX = 0001. So we are initializing it to FFFFH, after adding 2, it will be 0001H. In each iteration the counter value is increased, and subtract the BX ...
Read MoreHow to update a column of varchar type in MySQL to increase its length?
Let us first create a table. Here, we have two columns with varchar type −mysql> create table DemoTable ( UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, UserFirstName varchar(10), UserLastName varchar(20) , UserAge int ); Query OK, 0 rows affected (0.96 sec)Let us check the description of table using DESC command −mysql> desc DemoTable;This will produce the following output −+---------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | +---------------+-------------+------+-----+---------+----------------+ | UserId | int(11) | NO ...
Read MoreHow to send an error code using JSP to browser?
Following example shows how a 407 error code is sent to the client browser. After this, the browser would show you "Need authentication!!!" message. Setting HTTP Status Code You will receive the following output −HTTP Status 407 - Need authentication!!! type Status report message Need authentication!!! description The client must first authenticate itself with the proxy (Need authentication!!!). Apache Tomcat/5.5.29
Read More8086 program to convert an 8 bit BCD number into hexadecimal number
In this program we will see how to find the equivalent hexadecimal number from a BCD number.Problem StatementWrite 8086 Assembly language program to find the equivalent hexadecimal number from a BCD number. The number is stored at memory offset 500 and store the result at memory offset 600.DiscussionTo convert BCD to hexadecimal at first we have to cut the BCD digits. The most significant digit will be multiplied with 0AH (10D), and then least significant digit will be added with the result of multiplication. Thus the BCD will be converted to its equivalent hexadecimal form.InputAddressData……50059…… Flow Diagram ProgramOutputAddressData……6003B……
Read MoreIs it possible to delete everything after a 'space' in a MySQL field?
In order to delete everything after a space, you need to use SUBSTRING_INDEX().The syntax is as followsselect substring_index(yourColumnName, ' ', 1) as anyAliasName from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table deleteAfterSpaceDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(100) -> ); Query OK, 0 rows affected (0.55 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into deleteAfterSpaceDemo(StudentName) values('John Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into deleteAfterSpaceDemo(StudentName) ...
Read MoreHow to create MySQL user with limited privileges?
To create MySQL user with limited privileges, following is the syntax −CREATE USER 'yourUserName'@'yourHostName' IDENTIFIED BY 'yourPassword';Following is the syntax to set limited privileges for user −GRANT SELECT, INSERT, UPDATE, etc. REFERENCES ON yourDatabaseName.* TO 'yourUserName'@'yourHostName';Let us implement the above syntaxes in order to create a MySQL user with limited privileges −mysql> CREATE USER 'David'@'localhost' IDENTIFIED BY 'david'; Query OK, 0 rows affected (0.20 sec) mysql> GRANT SELECT, INSERT, UPDATE, DELETE, ALTER, CREATE, REFERENCES ON test.* TO 'David'@'localhost'; Query OK, 0 rows affected (0.21 sec)Let us check the user has been created with name ‘David’ or not.mysql> ...
Read More8086 program to sort an integer array in ascending order
In this program we will see how to sort array elements in ascending order.Problem StatementWrite 8086 Assembly language program to sort the elements in a given array, which is starts from memory offset 501. The size of the series is stored at memory offset 500.DiscussionHere we are sorting the number in bubble sorting technique. In this sorting technique there will be n passes for n different numbers. In ith pass the ith largest element will be placed at the end. This is comparison based sort. We taking two consecutive numbers, compare them, and then swap them if the numbers are ...
Read MoreHow to count null values in MySQL?
To count null values in MySQL, you can use CASE statement. Let us first see an example and create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(20) ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstName) values('John'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(FirstName) values(null); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(FirstName) values(''); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(FirstName) values('Larry'); Query OK, 1 row affected (0.17 ...
Read MoreHow to convert MySQL null to 0 using COALESCE() function?
You can use the COALESCE() function to convert MySQL null to 0SELECT COALESCE(yourColumnName, 0) AS anyAliasName FROM yourTableName;Let us first create a table. The query to create a table is as followsmysql> create table convertNullToZeroDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20), -> Salary int -> ); Query OK, 0 rows affected (1.28 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into convertNullToZeroDemo(Name, Salary) values('John', NULL); Query OK, 1 row affected (0.20 sec) mysql> insert into convertNullToZeroDemo(Name, Salary) values('Carol', 5610); Query OK, 1 ...
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