Database Articles - Page 307 of 546

Let us first create a table −mysql> create table DemoTable1    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> FirstName varchar(100)    -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1(FirstName) values('John'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1(FirstName) values('Chris'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable1;This will produce the following output −+----+-----------+ | Id | FirstName | +----+-----------+ | 1 | John ... Read More

For this, use BETWEEN operator in MySQL. Let us first create a table −mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    -> Start int,    -> End int    -> ); Query OK, 0 rows affected (0.91 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Start, End) values(100, 200); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Start, End) values(400, 500); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable(Start, End) values(210, 350); Query OK, 1 row affected (0.11 sec)Display all ... Read More

To add a new column to an existing table, use ADD. With that, to add a new index, use the ADD INDEX(). Let us first create a table −mysql> create table DemoTable    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(100),    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (0.69 sec)Let us check the description of the table −mysql> desc DemoTable;This will produce the following output −+-------+--------------+------+-----+---------+----------------+ | Field | Type         | Null | Key | Default | Extra          | +-------+--------------+------+-----+---------+----------------+ | Id ... Read More

Following is the syntax executing the plus (+) operator −update yourTableName set yourColumnName3=(yourColumnName1+yourColumnName2)The above syntax is only for plus operator. You need to change symbol like -, *, / for other operations. Let us first create a table −mysql> create table DemoTable    -> (    -> Number1 int,    -> Number2 int,    -> AddResult int,    -> MinusResult int,    -> MultiplyResult int,    -> DivideResult int    -> ); Query OK, 0 rows affected (0.89 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Number1, Number2) values(40, 20); Query OK, 1 row affected (0.16 ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> Number int    -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(12); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values(14); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(19); Query OK, 1 row affected (0.14 sec) ... Read More

Let us first create a table −mysql> create table DemoTable    -> (    -> StudentId varchar(100)    -> ); Query OK, 0 rows affected (0.71 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John19383'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Carol9999'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('David123456'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+-------------+ | StudentId   | +-------------+ | John19383 ... Read More

For this, use CASE statement. Let us first create a table −mysql> create table DemoTable    -> (    -> LastName varchar(100)    -> ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Smith'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Brown'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Brown'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Smith'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('Taylor'); Query OK, 1 ... Read More

Yes, you can use below syntax. Following is the syntax −PRIMARY KEY(yourColumnName1, yourColumnName2);Let us first create a table −mysql> create table DemoTable    -> (    -> StudentFirstName varchar(100),    -> StudentLastName varchar(100),    -> StudentAge int,    -> StudentCountryName varchar(100),    -> PRIMARY KEY(StudentFirstName, StudentLastName)    -> ); Query OK, 0 rows affected (0.74 sec)Let us check the description of the table −mysql> desc DemoTable;OutputThis will produce the following output −+--------------------+--------------+------+-----+---------+-------+ | Field              | Type         | Null | Key | Default | Extra | +--------------------+--------------+------+-----+---------+-------+ | StudentFirstName   | ... Read More

No, we cannot. If you still did it, then stored procedure won’t get created. Therefore, first you need to change your DELIMITER from semicolon(;) to others like (// ,??..etc). Following is the syntax −DELIMITER // CREATE PROCEDURE yourProcedureName() BEGIN yourStatement1, . . . . N END // DELIMITER ;Let us implement the above syntax in order to create a stored procedure −mysql> DELIMITER // mysql> CREATE PROCEDURE get_Message()    -> BEGIN    -> SELECT CONCAT("HELLO", " ", "MYSQL USERS");    -> END    -> // Query OK, 0 rows affected (0.23 sec) mysql> DELIMITER ;Now you can call the stored ... Read More

Use DatabaseMetaData class to retrieve MySQL database structure. In this example, we will display all the table names of database “web” using Java with the help of getMetaData().Following is the Java code −Exampleimport java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; import com.mysql.jdbc.DatabaseMetaData; public class getDatabaseInformationDemo {    public static void main(String[] args) {       Connection con = null;       try {          con = DriverManager.getConnection("jdbc:mysql://localhost:3306/web?useSSL=false", "root", "123456");          DatabaseMetaData information = (DatabaseMetaData) con.getMetaData();          String allTableName[] = {             "TABLE"   ... Read More