The SQL EXISTS is an operator that is used with the WHERE clause that tests the existence of rows by using a subquery.
If that subquery in the EXISTS contains any row, it returns TRUE.

The SQL has different clauses for fetching top records as using the SELECT statement. Different databases like MS SQL Server, MySQL and Oracle has different clauses for getting top records.

The SQL HAVING clause is generally used with the GROUP BY clause for specifying a condition for a group or aggregate.

The SQL BETWEEN operator is used to specify a range to test. You may use BETWEEN operator with SELECT statement for retrieving data for the given range. The BETWEEN operator can also be …

The “NOT IN” operators will return records that do not match the values given in the IN clause. The following example will make it clear.

The SQL TRUNCATE command is used to remove table data completely. You may also remove table data by using DELETE statement, however, there are certain differences as you execute the two.

The SQL TRIM function is used for removing the leading and trailing spaces from the given string. In this tutorial, I will show using in SQL Server, MySQL and Oracle

In RDBMS, the SQL JOIN clause is the way for combining records of different tables. The tables are joined by logical relationships.

To remove the duplicate records for the data fetched with SELECT statement, you may use the DISTINCT clause as shown in the examples in this tutorial.

The GROUP BY is a clause in SQL that is used with the SELECT statement for grouping the rows. The purpose is generally performing the aggregate operation like SUM, COUNT, AVG etc. to the group data.

The SQL MAX function is used to return the maximum value for the specified column in the SELECT statement. If the specified column is character based then highest value in the collating sequence is returned.

The ORDER BY clause in SQL is used to sort the results of a query in ascending or descending order. You may return the complete sorted result-set or optionally limit the rows by using the FETCH or OFFSET clauses.

The MS SQL Server and MySQL database ROUND function is used to return the number rounded to the specified precision.

The SQL SUM is an aggregate function that is used to return the sum of numeric column for all the values or DISTINCT values.

To get the count of rows returned by select statement, use the SQL COUNT function. In this tutorial, I will show 9 queries to learn about this.