Which of the following statements are TRUE about an SQL query?P : An S...
If we use a HAVING clause without a GROUP BY clause, the HAVING condition applies to
all rows that satisfy the search condition. In other words, all rows that satisfy the search
condition make up a single group. So, option P is true and Q is false.
S is also true as an example consider the following table and query.0
Select count (*)
From student
Group by Name
Output will be
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Which of the following statements are TRUE about an SQL query?P : An S...
Explanation:
P : An SQL query can contain a HAVING clause even if it does not have a GROUP BY clause
This statement is false. The HAVING clause is used to filter the results of a query based on a condition that applies to groups created by the GROUP BY clause. Therefore, a HAVING clause can only be used if there is a GROUP BY clause present in the SQL query. If there is no GROUP BY clause, there are no groups, and the HAVING clause becomes invalid.
Q : An SQL query can contain a HAVING clause only if it has a GROUP BY clause
This statement is true. As mentioned above, the HAVING clause is used to filter the results based on groups created by the GROUP BY clause. It cannot be used without a GROUP BY clause.
R : All attributes used in the GROUP BY clause must appear in the SELECT clause
This statement is true. In an SQL query with a GROUP BY clause, all attributes used in the GROUP BY clause must also appear in the SELECT clause. This is because the SELECT clause determines the columns that will be displayed in the result set, and the GROUP BY clause determines how the data will be grouped. To ensure consistency and avoid ambiguity, all attributes used for grouping must be included in the SELECT clause.
S : Not all attributes used in the GROUP BY clause need to appear in the SELECT clause
This statement is false. As mentioned in the previous point, all attributes used in the GROUP BY clause must appear in the SELECT clause. This is to ensure that the result set is consistent and unambiguous.
Therefore, the correct statements are:
- R : All attributes used in the GROUP BY clause must appear in the SELECT clause
- Q : An SQL query can contain a HAVING clause only if it has a GROUP BY clause
Hence, the correct answer is option 'C'.
Which of the following statements are TRUE about an SQL query?P : An S...
S statement is true then why is the option c is true
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