Quick Answer: Can We Use Count In Where Clause?

Can we write select statement in case?

The CASE statement always goes in the SELECT clause.

CASE must include the following components: WHEN , THEN , and END .

ELSE is an optional component.

You can make any conditional statement using any conditional operator (like WHERE ) between WHEN and THEN ..

What is the difference between where and having clause?

WHERE Clause is used to filter the records from the table based on the specified condition. … HAVING Clause is used to filter record from the groups based on the specified condition.

How do I select duplicate rows in SQL?

To select duplicate values, you need to create groups of rows with the same values and then select the groups with counts greater than one. You can achieve that by using GROUP BY and a HAVING clause.

Can we use having and where clause in a same query?

A query can contain both a WHERE clause and a HAVING clause. … The HAVING clause is then applied to the rows in the result set. Only the groups that meet the HAVING conditions appear in the query output. You can apply a HAVING clause only to columns that also appear in the GROUP BY clause or in an aggregate function.

Can we use case in where clause in Oracle?

Introduction to Oracle CASE expression You can use a CASE expression in any statement or clause that accepts a valid expression. For example, you can use the CASE expression in statements such as SELECT , UPDATE , or DELETE , and in clauses like SELECT , WHERE , HAVING , and ORDDER BY .

What is SQL function with example?

Aggregate SQL FunctionsFunctionDescriptionSUM()Used to return the sum of a group of values.COUNT()Returns the number of rows either based on a condition, or without a condition.AVG()Used to calculate the average value of a numeric column.MIN()This function returns the minimum value of a column.3 more rows•Oct 14, 2019

Why having clause is used in SQL?

The HAVING clause specifies a search condition for a group. You often use the HAVING clause with the GROUP BY clause. The GROUP BY clause groups a set of rows into a set of summary rows or groups. Then the HAVING clause filters groups based on a specified condition.

Can function be used in where clause?

SQL Server offers many handy functions that can be used either in your SELECT clause or in your WHERE clause. For the most part these functions provide complex coding that would be very difficult to get this same functionality without these functions.

Can we use case in where clause?

CASE can be used in any statement or clause that allows a valid expression. For example, you can use CASE in statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as select_list, IN, WHERE, ORDER BY, and HAVING.

What is difference between stored procedure and function?

The function must return a value but in Stored Procedure it is optional. Even a procedure can return zero or n values. Functions can have only input parameters for it whereas Procedures can have input or output parameters. Functions can be called from Procedure whereas Procedures cannot be called from a Function.

What is @@ in SQL?

In SQL Server, symbol @@ is prefixed to global variables. The server maintains all the global variables. … Global variable names begin with a @@ prefix. You do not need to declare them, since the server constantly maintains them. They are system-defined functions and you cannot declare them.

How do you use count in having clause?

SQL Server HAVING with the COUNT function exampleFirst, the GROUP BY clause groups the sales order by customer and order year. The COUNT() function returns the number of orders each customer placed in each year.Second, the HAVING clause filtered out all the customers whose number of orders is less than two.

What are the different functions in SQL?

SQL FunctionsAVG() – Returns the average value.COUNT() – Returns the number of rows.FIRST() – Returns the first value.LAST() – Returns the last value.MAX() – Returns the largest value.MIN() – Returns the smallest value.SUM() – Returns the sum.

What does count 1 mean SQL?

COUNT(1) is basically just counting a constant value 1 column for each row. As other users here have said, it’s the same as COUNT(0) or COUNT(42) . Any non- NULL value will suffice.

Can we call function in SQL query?

A function is a set of SQL statements that perform a specific task. Functions foster code reusability. … Next time instead of rewriting the SQL, you can simply call that function. A function accepts inputs in the form of parameters and returns a value.

What is the difference between inline table valued function and multi statement?

Inline table valued function refers to a TVF where the function body just contains one line of select statement. … Multi-statement table valued function refers to a TVF where it has a return table variable. Inside the function body, there will be statements populating this table variable.

What are triggers in SQL?

A trigger is a special type of stored procedure that automatically runs when an event occurs in the database server. DML triggers run when a user tries to modify data through a data manipulation language (DML) event. … SQL Server lets you create multiple triggers for any specific statement.

Which is faster where or having?

Both the statements will be having same performance as SQL Server is smart enough to parse both the same statements into a similar plan. So, it does not matter if you use WHERE or HAVING in your query. … “WHERE” is faster than “HAVING”!

What is the use of order by clause?

The SQL ORDER BY Keyword The ORDER BY keyword is used to sort the result-set in ascending or descending order. The ORDER BY keyword sorts the records in ascending order by default. To sort the records in descending order, use the DESC keyword.

Can we use function in select statement?

The syntax is similar to the one that creates a user-defined function. The RETURNS TABLE specifies that the function will return a table. … The function above returns the result set of a single SELECT statement, therefore, it is also known as an inline table-valued function.

How do I do an if statement in SQL?

Syntax. In the following SQL IF Statement, it evaluates the expression, and if the condition is true, then it executes the statement mentioned in IF block otherwise statements within ELSE clause is executed. We can understand SQL IF Statement using the following flow chart.