GROUP BY clause

Question

If aggregate functions are used in the select clause along with attribute list we must use group by clause for grouping the attribute values ?

SELECT a1, COUNT(*) FROM Employee

Is above query  right or  wrong ?

Comments

should be wrong...

the query should be like

SELECT a1, COUNT(*)

FROM Employee

groupby a1

---

Means you are saying that whenever aggregate functions are used in the select clause along with attribute list then groupby clause must be present in the query ,right?

---

yes

---

count doesnot need group by

even having also doesnot need group by every time

right?

---

but in this example he used attribute in select clause, therefore it must required groupby clause

if there is no attribute used in select clause, then your statements are true

---

This query will ouput 1'st value of a1 along with number of rows in relation which are not null.