Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles by karthikeya Boyini
Page 124 of 143
Sum if all rows are not null else return null in MySQL?
You can achieve this with the help of GROUP BY HAVING clause. The syntax is as follows −SELECT yourColumnName1, SUM(yourCoumnName2) from yourTableName GROUP BY yourColumnName1 HAVING COUNT(yourCoumnName2) = COUNT(*);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table SumDemo -> ( -> Id int, -> Amount int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SumDemo values(1, 200); Query OK, 1 row affected (0.22 ...
Read MoreWhat is import attribute in JSP?
The import attribute serves the same function as and behaves like, the Java import statement. The value for the import option is the name of the package you want to import.To import java.sql.*, use the following page directive −To import multiple packages, you can specify them separated by comma as follows −By default, a container automatically imports java.lang.*, javax.servlet.*, javax.servlet.jsp.*, and javax.servlet.http.*.
Read MoreMySQL "order by" inside of "group by"? Is it possible?
Instead of using ORDER BY inside GROUP BY, you can use the MAX() aggregate function.The syntax is as follows −SELECT yourNameColumnName, MAX(yourRankColumnName) FROM yourTableName GROUP BY yourNameColumnName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table MaxDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(20), -> UserRank int -> ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into MaxDemo(UserName, UserRank) values('Larry', 2); Query ...
Read MoreWhat is isThreadSafe attribute in JSP?
The isThreadSafe option marks a page as being thread-safe. By default, all JSPs are considered thread-safe. If you set the isThreadSafe option to false, the JSP engine makes sure that only one thread at a time is executing your JSP.The following page directive sets the isThreadSafe option to false −
Read MoreMySQL select accumulated (running sum) column?
To select accumulated column, let us first create a demo table. The query to create a table is as follows −mysql> create table accumulatedDemo -> ( -> Value int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into accumulatedDemo values(10); Query OK, 1 row affected (0.21 sec) mysql> insert into accumulatedDemo values(15); Query OK, 1 row affected (0.09 sec) mysql> insert into accumulatedDemo values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into accumulatedDemo values(25); Query OK, 1 row affected ...
Read MoreDisplay the warning message when a FLOAT value is inserted into DECIMAL in MySQL?
You can create a temporary table with data type DECIMAL to get a warning when a float value is inserted into an int column. Display the same warning using SHOW WARNINGS.Let us create a table to understand. The query is as follows to create a table.mysql> create temporary table WarningDemo -> ( -> Value DECIMAL -> ); Query OK, 0 rows affected (0.13 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into WarningDemo values(9.80); Query OK, 1 row affected, 1 warning (0.03 sec)Here we are getting a warning. Let ...
Read MoreWhat is session attribute in JSP?
The session attribute indicates whether or not the JSP page uses HTTP sessions. A value of true means that the JSP page has access to a builtin session object and a value of false means that the JSP page cannot access the builtin session object.Following directive allows the JSP page to use any of the builtin object session methods such as session.getCreationTime() or session.getLastAccessTime() −
Read MoreCan we test XPath expression in JSP?
The tag evaluates a test XPath expression and if it is true, it processes its body. If the test condition is false, the body is ignored.AttributeThe tag has the following attributes −AttributeDescriptionRequiredDefaultselectThe XPath expression to be evaluatedYesNonevarName of the variable to store the condition's resultNoNonescopeScope of the variable specified in the var attributeNoPageExampleFollowing is an example that show the use of the tag − JSTL x:if Tags Books Info: ...
Read MoreWhat is isScriptingEnabled Attribute in JSP?
The isScriptingEnabled attribute determines if the scripting elements are allowed for use.The default value (true) enables scriptlets, expressions, and declarations. If the attribute's value is set to false, a translation-time error will be raised if the JSP uses any scriptlets, expressions (non-EL), or declarations.The attribute's value can be set to false if you want to restrict the usage of scriptlets, expressions (non-EL), or declarations −
Read MoreCreate an aggregate checksum of a column in MySQL
You can use CRC32 checksum for this. The syntax is as follows −SELECT SUM(CRC32(yourColumnName)) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table CRC32Demo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserId varchar(20) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into CRC32Demo(UserId) values('USER-1'); Query OK, 1 row affected (0.38 sec) mysql> insert into CRC32Demo(UserId) values('USER-123'); Query OK, 1 row ...
Read More