What is GROUP BY in PL SQL?

PL/SQL Group By statement is used for getting the summary information of the particular columns of the table, and the rows of the tables are used to form groups based on one or more rows of the table. The group by clause is used along with the SELECT statement in PL/SQL, which is for retrieving the grouped information.

Can we use GROUP BY clause in subquery in Oracle?

Did you look up “GROUP BY” in the SQL Language manual? This clause is subject to the following restrictions: You cannot specify LOB columns, nested tables, or varrays as part of expr. The expressions can be of any form except scalar subquery expressions.

Is GROUP BY mandatory for having clause?

The groupby clause is used to group the data according to particular column or row. 2. Having can be used without groupby clause,in aggregate function,in that case it behaves like where clause. groupby can be used without having clause with the select statement.

What is the purpose of GROUP BY clause?

The GROUP BY Clause is utilized in SQL with the SELECT statement to organize similar data into groups. It combines the multiple records in single or more columns using some functions.

Can we use GROUP BY without aggregate function in Oracle?

You can use the GROUP BY clause without applying an aggregate function. The following query gets data from the payment table and groups the result by customer id. In this case, the GROUP BY works like the DISTINCT clause that removes duplicate rows from the result set.

Can we use alias in GROUP BY clause in Oracle?

In Oracle you cannot use an alias in a group by clause.

Can I work without GROUP BY?

A query with a having clause should also have a group by clause. If you omit group by, all the rows not excluded by the where clause return as a single group. Because no grouping is performed between the where and having clauses, they cannot act independently of each other.

What is the difference between HAVING and GROUP BY clause?

We can use the WHERE clause with the SELECT, UPDATE, and DELETE statements. The HAVING clause can only use with the SELECT statement. The GROUP BY clause comes after the WHERE clause. The GROUP BY clause comes before the HAVING clause.

WHERE we can use GROUP BY clause?

GROUP BY clause is used with the SELECT statement. In the query, GROUP BY clause is placed after the WHERE clause. In the query, GROUP BY clause is placed before ORDER BY clause if used any.

Can we use GROUP BY without count?

Using COUNT, without GROUP BY clause will return a total count of a number of rows present in the table. Adding GROUP BY, we can COUNT total occurrences for each unique value present in the column.