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Answered by: Ranjeet

• Feb 27th, 2006

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Emp_name varchar(10) -  if you enter value less than 10 then remaining space can not be deleted. it used total 10 spaces.

Emp_name varchar2(10) - if you enter value less than 10 then remaining space is automatically deleted

Krishna Kant Kumar

• Mar 12th, 2019

VARCHAR is going to be replaced by VARCHAR2 in next version. So, Oracle suggests the use VARCHAR2 instead of VARCHAR while declaring data type. VARCHAR can store up to 2000 bytes of characters while ...

Prabhat Sahu

 Profile Answers by Prabhat Sahu Questions by Prabhat Sahu

• Oct 30th, 2018

CHARACTER Datatype: CHAR, VARCHAR both are of CHARACTER Datatype in oracle. CHAR is fixed length datatype and VARCHAR is Variable length datatype to store character data. i.e. A-Z , a-z , 0-9 and key...

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Answered by: Ankush Sharma

• Sep 14th, 2011

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Though the HAVING clause specifies a condition that is similar to the purpose of a WHERE clause, the two clauses are not interchangeable. Listed below are some differences to help distinguish between the two:

1. The WHERE clause specifies the criteria which individual records must meet to be selcted by a query. It can be used without the GROUP BY clause. The HAVING clause cannot be used without the GROUP BY clause.
2. The WHERE clause selects rows before grouping. The HAVING clause selects rows after grouping.
3. The WHERE clause cannot contain aggregate functions. The HAVING clause can contain aggregate functions.

for Example: if for an "Select" statement we use the "where" clause then the the result based on the "where" condition results and then we can use "group by" clause to arrange in some order, Now if we want to impose the condition on that group then we use "having" clause.

The main reason for using WHERE clause is to select rows that are to be included in the query. For example, assume table Test.Suppose I want the names, account numbers, and balance due of all customers from California and Los Angles. Since STATE is one of the fields in the record format, I can use WHERE to select those customers.

Using the code

Code
SELECT cusnum, lstnam, init
FROM Test
WHERE state IN ('CA', 'LA')
 
CUSNUM LSTNAM INIT BALDUE
====== ============ ==== ========
938472 John G K 37.00
938485 Mark J A 3987.50
593029 Lily E D 25.00

Suppose I want the total amount due from customers by state. In that case, I would need to use the GROUP BY clause to build an aggregate query.

Code
SELECT state,SUM(baldue)
FROM Test
GROUP BY state
ORDER BY state
 
State Sum(Baldue)
===== ===========
CA 250.00
CO 58.75
GA 3987.50
MN 510.00
NY 589.50
TX 62.00
VT 439.00
WY .00

Using Having

Code
SELECT state,SUM(baldue)
FROM Test
GROUP BY state
HAVING SUM(baldue) > 250
 
 
State Sum(Baldue)
===== ===========
GA 3987.50
MN 510.00
NY 589.50
VT 439.00

Ankush Sharma

• Sep 14th, 2011

Though the HAVING clause specifies a condition that is similar to the purpose of a WHERE clause, the two clauses are not interchangeable. Listed below are some differences to help distinguish between ...

Ankush Sharma

• Sep 14th, 2011

Though the HAVING clause specifies a condition that is similar to the purpose of a WHERE clause, the two clauses are not interchangeable. Listed below are some differences to help distinguish between ...

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