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Articles by Samual Sam
Page 133 of 151
What are JSP literals?
The JSP expression language defines the following literals −Boolean − true and falseInteger − as in JavaFloating point − as in JavaString − with single and double quotes; " is escaped as ", ' is escaped as ', and \ is escaped as \.Null − null
Read MoreHow to convert string to bitset in MySQL?
To convert string to bitset, use the CONV() method. Let us first create a table −mysql> create table DemoTable ( stringValue BIT(4) ); Query OK, 0 rows affected (3.50 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(CONV('1110', 2, 10) * 1); Query OK, 1 row affected (0.62 sec) mysql> insert into DemoTable values(b'1011'); Query OK, 1 row affected (0.14 sec)Following is the query to display all records from the table using select statement −mysql> select *from DemoTable;Following is the output that displays blank result because the type is bitset −Following is the query ...
Read MoreHow to check whether column value is NULL or having DEFAULT value in MySQL?
You can use the concept of IFNULL() for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(100) DEFAULT 'Larry', Age int DEFAULT NULL ); Query OK, 0 rows affected (0.73 sec)Insert records in the table using insert command −mysql> insert into DemoTable(Name, Age) values('John', 23); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(); Query OK, 1 row affected (0.34 sec) mysql> insert into DemoTable(Name) values('David'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable(Age) values(24); Query OK, 1 row ...
Read MoreMySQL query to get sum of each column where every column has same number of values?
You can use aggregate function SUM() for this. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstValue int, SecondValue int, ThirdValue int ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(10, 20, 30); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(60, 50, 40); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(FirstValue, SecondValue, ThirdValue) values(80, 90, 100); Query OK, 1 row affected ...
Read MoreDelete last 4 letters in MySQL?
You can use SUBSTRING() along with UPDATE command to delete last 4 letters. Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentSubject varchar(100) ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentSubject) values('Introduction to Java'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable(StudentSubject) values('Introduction to C'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentSubject) values('Introduction to C++'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable(StudentSubject) values('Spring And Hibernate'); ...
Read MoreMySQL command-line tool: How to find out number of rows affected by a DELETE?
You can use row_count() at the end for this. Let us first create a table −mysql> create table rowAfftectedByDeleteDemo -> ( -> CustomerId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> CustomerName varchar(20) -> ); Query OK, 0 rows affected (0.86 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into rowAfftectedByDeleteDemo(CustomerName) values('John'); Query OK, 1 row affected (0.14 sec) mysql> insert into rowAfftectedByDeleteDemo(CustomerName) values('Carol'); Query OK, 1 row affected (0.10 sec) mysql> insert into rowAfftectedByDeleteDemo(CustomerName) values('Bob'); Query OK, 1 row affected (0.09 sec) mysql> insert into rowAfftectedByDeleteDemo(CustomerName) values('Sam'); Query ...
Read MoreHow to export specific column data in MySQL?
To export specific column data in MySQL, use OUTFILE −select yourColumnName from yourTableName into outfile 'yourLocationOfFile’;Let us first create a table −mysql> create table DemoTable ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentFirstName varchar(20), StudentLastName varchar(20) ); Query OK, 0 rows affected (0.54 sec)Insert records in the table using insert command −mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('John', 'Doe'); Query OK, 1 row affected (0.26 sec) mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('David', 'Miller'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(StudentFirstName, StudentLastName) values('John', 'Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into ...
Read MoreMySQL GROUP BY date when using datetime?
To GROUP BY date while using datetime, the following is the syntax −select *from yourTableName GROUP BY date(yourColumnName);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table groupByDateDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(20), -> UserPostDatetime datetime -> ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into groupByDateDemo(UserName, UserPostDatetime) values('Larry', '2018-01-02 13:45:40'); Query OK, 1 row affected (0.18 sec) mysql> insert ...
Read MoreWhere is the MySQL table data stored in Windows?
In order to know the location of MySQL table data, you can use the below syntax −select @@datadir;You can also use SHOW VARIABLES command for this. Following is the syntax −show variables where Variable_name ='datadir';Let us implement the above syntaxes to know where MySQL table stores data −mysql> select @@datadir;This will produce the following output −+---------------------------------------------+ | @@datadir | +---------------------------------------------+ | C:\ProgramData\MySQL\MySQL Server 8.0\Data\ | +---------------------------------------------+ ...
Read MoreDifference between Synchronized ArrayList and CopyOnWriteArrayList in Java
Synchronized ArrayList and CopyOnWriteArrayList are useful for synchronizing the ArrayList. This is necessary for a multi-threaded environment to make sure thread safety is achieved.The differences between Synchronized ArrayList and CopyOnWriteArrayList are given as follows −Synchronized ArrayListCopyOnWriteArrayListSynchronized ArrayList is used to synchronize the ArrayList.CopyOnWriteArrayList is used to synchronize the ArrayList.The Java 1.2 version first introduced the Synchronized ArrayList.The Java 1.5 version first introduced the CopyOnWriteArrayList.The Synchronized ArrayList should be used when there are more write operations than reading operations in ArrayList.The CopyOnWriteArrayList should be used when there are more read operations than write operations in ArrayList.This iterator is a fail-fast iterator.This ...
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