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Tag Archives: SQL

Overview – SQL

Overview – SQL tutorial gives unique learning on Structured Query Language and it helps to make practice on SQL commands which provides immediate results. SQL is a language of database, it includes database creation, deletion, fetching rows and modifying rows etc. SQL is an ANSI (American National Standards Institute) standard but there are many different versions of the SQL language. ...

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Update Query – SQL

Update Query – SQL is used to modify the existing records in a table. You can use WHERE clause with UPDATE query to update selected rows otherwise all the rows would be affected. Syntax: The basic syntax of UPDATE query with WHERE clause is as follows: UPDATE table_name SET column1 = value1, column2 = value2...., columnN = valueN WHERE [condition]; ...

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Using Views – SQL

Using Views – SQL –  is nothing more than a SQL statement that is stored in the database with an associated name. A view is actually a composition of a table in the form of a predefined SQL query. A view can contain all rows of a table or select rows from a table. A view can be created from ...

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SUM Function SQL

SUM Function SQL is used to find out the sum of a field in various records. To understand SUM function, consider an employee_tbl table, which is having the following records: SQL> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | ...

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RDBMS Concepts – SQL

What is RDBMS? RDBMS stands for Relational Database Management System. RDBMS is the basis for SQL, and for all modern database systems like MS SQL Server, IBM DB2, Oracle, MySQL, and Microsoft Access. A Relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd. What is ...

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Delete Query – SQL

Delete Query – SQL is used to delete the existing records from a table. You can use WHERE clause with DELETE query to delete selected rows, otherwise all the records would be deleted. Syntax: The basic syntax of DELETE query with WHERE clause is as follows: DELETE FROM table_name WHERE [condition]; You can combine N number of conditions using AND ...

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Having Clause – SQL

Having Clause – SQL enables you to specify conditions that filter which group results appear in the final results. The WHERE clause places conditions on the selected columns, whereas the HAVING clause places conditions on groups created by the GROUP BY clause. Syntax: The following is the position of the HAVING clause in a query: SELECT FROM WHERE GROUP BY ...

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SQRT Function SQL

SQRT Function SQL is used to find out the square root of any number. You can Use SELECT statement to find out square root of any number as follows: SQL> select SQRT(16); +----------+ | SQRT(16) | +----------+ | 4.000000 | +----------+ 1 row in set (0.00 sec) You are seeing float value here because internally SQL will manipulate square root ...

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Databases – SQL

Databases – SQL There are many popular RDBMS available to work with. This tutorial gives a brief overview of few most popular RDBMS. This would help you to compare their basic features. MySQL MySQL is an open source SQL database, which is developed by Swedish company MySQL AB. MySQL is pronounced “my ess-que-ell,” in contrast with SQL, pronounced “sequel.” MySQL ...

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LIKE Clause – SQL

LIKE Clause – SQL is used to compare a value to similar values using wildcard operators. There are two wildcards used in conjunction with the LIKE operator: The percent sign (%) The underscore (_) The percent sign represents zero, one, or multiple characters. The underscore represents a single number or character. The symbols can be used in combinations. Syntax: The ...

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