Can we give alias in GROUP BY clause?

Can we give alias in GROUP BY clause?

SQL Server doesn’t allow you to reference the alias in the GROUP BY clause because of the logical order of processing. The GROUP BY clause is processed before the SELECT clause, so the alias is not known when the GROUP BY clause is evaluated. This also explains why you can use the alias in the ORDER BY clause.

Can we specify alias name in HAVING clause?

Alias is not allowed in HAVING clause and this is why. or department_id could also be used with HAVING clause. In other words, HAVING clause will accept any argument that is present in the SELECT statement. The purpose of HAVING clause is to limit GROUP BY results.

Can I use alias in HAVING?

In PROC SQL, a column alias can be used in a WHERE clause, ON clause, GROUP BY clause, HAVING clause, or ORDER BY clause. In the ANSI SQL standard and ISO SQL standard, the value that is associated with a column alias does not need to be available until the ORDER BY clause is executed.

Can ORDER BY use aliases?

An ORDER BY clause can specify any combination of column names, column aliases, and select-item column numbers.

When to use column alias in group by clause?

A column alias may be used in the ORDER BY clause but not in the GROUP BY clause. If you look at the syntax diagrams this becomes obvious: The order by clause is defined as: So after the ORDER BY an expression is allowed, a position (order by 1) or a c_alias which stands for “column alias”. The group by is defined as:

When do you use aliases in a table?

Table aliases can be used in SELECT lists and in the FROM clause to show the complete record or selective columns from a table. Table aliases can be used in WHERE, GROUP BY, HAVING, and ORDER BY clauses. When we need data from multiple tables, we need to join those tables by qualifying the columns using table name/table alias.

When to use reserved keywords in column alias?

The keyword AS can be used between the column or table name and the alias name, but this is optional. Also, we can use reserved keywords as a column alias, but not for tables. If we want the reserved keywords as alias then we need to keep those reserved words within double quotes.

Is there a SELECT clause for grouping in SQL?

In the SELECT clause of a query with grouping, you only have access to the GROUP BY expressions and aggregated values. So it’s not about being smart; it has to be implemented that way for the grouping to work. (And it’s required by the SQL standard).