MySQL Articles - Page 248 of 402

The syntax is as follows to rename Root @localhostUPDATE MySQL.user SET user = ‘yourNewRootName’ WHERE user = 'root';To understand the above concept, let us check all the user names and host. The query is as followsmysql> select user, host from MySQL.user;The following is the output+------------------+-----------+ | user             | host      | +------------------+-----------+ | Bob              | %         | | Manish           | %         | | User2            | %       ... Read More

You can use UNION to get the previous and next record in MySQL.The syntax is as follows(select *from yourTableName WHERE yourIdColumnName > yourValue ORDER BY yourIdColumnName ASC LIMIT 1) UNION (select *from yourTableName WHERE yourIdColumnName < yourValue ORDER BY yourIdColumnName DESC LIMIT 1);To understand the concept, let us create a table. The query to create a table is as followsmysql> create table previousAndNextRecordDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Name varchar(30) - > ); Query OK, 0 rows affected (1.04 ... Read More

Yes, it is possible to calculate a correlation in a query. To understand the correlation in a query, you need to first create a table. The query to create a table is as followsmysql> create table correlationDemo - > ( - > value float not null, - > value2 float not null - > ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table with the help of insert command. The query is as follows to insert records in the tablemysql> insert into correlationDemo values(1, ... Read More

Let us first create a table. The query to create a table is as followsmysql> create table selectAllDemo - > ( - > Name varchar(100), - > Age int - > ); Query OK, 0 rows affected (1.90 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into selectAllDemo values('John', 25); Query OK, 1 row affected (0.99 sec) mysql> insert into selectAllDemo values('Carol', 26); Query OK, 1 row affected (0.42 sec) mysql> insert into selectAllDemo values('Bob', 30); Query OK, 1 row affected (1.57 ... Read More

You can use CASE statement to count two different columns in a single query. To understand the concept, let us first create a table. The query to create a table is as follows.mysql> create table CountDifferentDemo    - > (    - > ProductId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    - > ProductName varchar(20),    - > ProductColor varchar(20),    - > ProductDescription varchar(20)    - > ); Query OK, 0 rows affected (1.06 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into CountDifferentDemo(ProductName, ProductColor, ProductDescription) values('Product-1', 'Red', 'Used'); Query OK, 1 row ... Read More

For this, use the substring_index() function.The syntax is as followsselect substring_index(yourColumnName, '. ', -1) AS anyAliasNamefrom yourTableName;Let us first create a table. The query to create a table is as followsmysql> create table AllFiles - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > UserName varchar(10), - > FileName varchar(100) - > ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into AllFiles(UserName, FileName) values('Larry', 'AddTwoNumber.java'); Query OK, 1 ... Read More

You can achieve this with the help of prepared statement in MySQL. First you need to create a table. The query to create a table is as followsmysql> create table University - > ( - > UserId int, - > UniversityId int - > ); Query OK, 0 rows affected (0.64 sec)At first, let us set values in the above-mentioned columns. Here, we have set a string with comma separated value for UserId column. We will split this and insert in the tablemysql> SET @userId = '8, 9, ... Read More

To get data from MySQL database, you need to use executeQuery() method from java. First create a table in the MySQL database. Here, we will create the following table in the ‘sample’ databasemysql> create table javaGetDataDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > FirstName varchar(10), - > LastName varchar(10) - > ); Query OK, 0 rows affected (0.80 sec)Now you can insert some records in the table using insert command.The query is as followsmysql> insert into javaGetDataDemo(FirstName, LastName) values('John', 'Smith'); Query OK, 1 row affected (0.19 sec) mysql> insert into javaGetDataDemo(FirstName, LastName) values('Carol', ... Read More

You need to use unsigned for this because it won’t allow you to enter a negative number.The syntax is as followsCREATE TABLE yourTableName ( yourColumnName INT UNSIGNED );To understand the concept, let us create a table. The query to create a table is as followsmysql> create table OnlyPositiveValue - > ( - > Marks int UNSIGNED - > ); Query OK, 0 rows affected (0.58 sec)Before inserting data in the table, use the below query.The query is as followsmysql> SET @@SESSION.sql_mode = 'STRICT_TRANS_TABLES'; Query OK, 0 rows affected, ... Read More

Yes, it is possible to enforce data checking in MySQL using regular expression. First, you need to create a table. After that you need to create a trigger before insert in table. Here, we will be checking the Phone Number format.The query to create a table is as followsmysql> create table enforceDataUsingRegularExpression - > ( - > yourPhoneNumber varchar(60) - > ); Query OK, 0 rows affected (0.59 sec)The query to create a trigger is as followsmysql> DELIMITER // mysql> CREATE TRIGGER enforce_phone_check BEFORE INSERT ON enforceDataUsingRegularExpression - ... Read More