How to add new hard disk in centos Finding the New Hard Drive in CentOS 6 Assuming the drive is visible to the BIOS it should automatically be detected by the operating system. Typically, the disk drives in a system are assigned device names beginning hd or sd followed by a letter to indicate the … Read more
How to Install MySQL 8.0 on CentOS 7 MySQL is an open-source free relational database management system (RDBMS) released under GNU (General Public License). It is used to run multiple databases on any single server by providing multi-user access to each created database. Step 1: Adding the MySQL Yum Repository 1. We will use the … Read more
MySQL JOINS MySQL JOINS are used with SELECT statement. It is used to retrieve data from multiple tables. It is performed whenever you need to fetch records from two or more tables. There are three types of MySQL joins: MySQL INNER JOIN (“or sometimes called simple join”) MySQL LEFT OUTER JOIN (“or sometimes called LEFT … Read more
MySQL AND Condition The MySQL AND condition is used with SELECT, INSERT, UPDATE or DELETE statements to test two or more conditions in an individual query. Syntax: WHERE condition1 AND condition2 … AND condition_n; Parameter explanation: condition1, condition2, … condition_n: Specifies all conditions that must be fulfilled for the records to be selected. MySQL AND Example The following … Read more
MySQL HAVING Clause MySQL HAVING Clause is used with GROUP BY clause. It always returns the rows where condition is TRUE. Syntax: SELECT expression1, expression2, … expression_n, aggregate_function (expression) FROM tables [WHERE conditions] GROUP BY expression1, expression2, … expression_n HAVING condition; Parameters aggregate_function: It specifies any one of the aggregate function such as SUM, COUNT, MIN, MAX, or AVG. expression1, expression2, … expression_n: It specifies the expressions that … Read more
MySQL GROUP BY Clause The MYSQL GROUP BY Clause is used to collect data from multiple records and group the result by one or more column. It is generally used in a SELECT statement. You can also use some aggregate functions like COUNT, SUM, MIN, MAX, AVG etc. on the grouped column. Syntax: SELECT expression1, expression2, … expression_n, aggregate_function (expression) … Read more
MySQL ORDER BY Clause The MYSQL ORDER BY Clause is used to sort the records in ascending or descending order. Syntax: SELECT expressions FROM tables [WHERE conditions] ORDER BY expression [ ASC | DESC ]; Parameters expressions: It specifies the columns that you want to retrieve. tables: It specifies the tables, from where you want to retrieve records. There must be at least one table … Read more
MySQL FROM Clause The MySQL FROM Clause is used to select some records from a table. It can also be used to retrieve records from multiple tables using JOIN condition. Syntax: FROM table1 [ { INNER JOIN | LEFT [OUTER] JOIN| RIGHT [OUTER] JOIN } table2 ON table1.column1 = table2.column1 ] Parameters table1 and table2: specify tables used in the MySQL statement. The two tables are joined based on table1.column1 = table2.column1. … Read more
MySQL Distinct Clause MySQL DISTINCT clause is used to remove duplicate records from the table and fetch only the unique records. The DISTINCT clause is only used with the SELECT statement. Syntax: SELECT DISTINCT expressions FROM tables [WHERE conditions]; Parameters expressions: specify the columns or calculations that you want to retrieve. tables: specify the name of the tables from … Read more
MySQL WHERE Clause MySQL WHERE Clause is used with SELECT, INSERT, UPDATE and DELETE clause to filter the results. It specifies a specific position where you have to do the operation. Syntax: WHERE conditions; Parameter: conditions: It specifies the conditions that must be fulfilled for records to be selected. MySQL WHERE Clause with single condition Let’s … Read more