In this article, we will learn how to use the EXISTS operator in SQL.
The EXISTS operator is used to checking the presence of any record in a subquery.
If the subquery returns one or more records, the EXISTS operator returns true.
In this article, we will learn how to use the HAVING clause in SQL.
The WHERE clause could not be used with aggregate functions, so the HAVING clause was added to SQL.
In this article, we will learn how to use the GROUP BY keyword in SQL.
The GROUP BY statement is used to group rows that have the same values.
The GROUP BY statement is usually used with aggregate functions to group the result-set by one or more columns.
In this article, we will learn how to use the UNION operator in SQL.
To combine the result-set of multiple SELECT statements, the UNION operator is used.
Within UNION each SELECT statement must have the same number of columns.
The columns must also have similar data types.
The columns must also be in the same order in each SELECT statement.
In this article, we will learn how to use the CROSS JOIN keyword in SQL.
The CROSS JOIN keyword is used to combine each row of the first table with each row from the second table, also known as CARTESIAN JOIN.
In general words, we can say that the CROSS JOIN keyword is used to select the Cartesian product of the sets of rows from the joined table.
In this article, we will learn how to use the FULL OUTER JOIN keyword in SQL. The FULL OUTER JOIN is also known as FULL JOIN.
The FULL OUTER JOIN keyword is used to select all records from both tables.
The columns of the left table will have nulls when no matching rows exist for the row in the right table. Similarly, The columns of the right table will have nulls when no matching rows exist for the row in the left table.
In this article, we will learn how to use the RIGHT JOIN keyword in SQL.
The RIGHT JOIN keyword is used to select all records from the table2 (right table), and the matched records from the table1 (left table). If there is no match, the result from the left side is NULL.
In this article, we will learn how to use the LEFT JOIN keyword in SQL.
The LEFT JOIN keyword is used to select all records from the table1 (left table), and the matched records from the table2 (right table). If there is no match, the result from the right side is NULL.
In this article, we will learn about how we can perform crud operations using ADO.NET in ASP.NET.
