Monday, 12 September 2016

Difference between Group By and Partition By.

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Group By Clause Partition By Clause Reduces the no. of records No. of records will not be reduced ...
Wednesday, 15 June 2016

How to find duplicate records if one of the column has unique value.

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SELECT Count (*) FROM ( SELECT DISTINCT Col1 , Col2 , Col3 FROM tab...
Thursday, 2 June 2016

Difference Between IN and EXISTS

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IN EXIST 1 IN  is faster than  EXISTS , when the sub-query results is very small. EXISTS...
Sunday, 29 May 2016

Difference Between VIEW and Materialized View

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View Materialized view 1.  In Views query result is not stored in the disk or database. 1. Mater...

Difference Between CASE and DECODE

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CASE DECODE 1.CASE expression complies with ANSI SQL 1. DECODE is specific to Database vendors...
Monday, 14 March 2016

Cumulative Sum or LAG function Example

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 SELECT EMPNO, ENAME, SAL, NVL(SAL,0)+LAG(SAL,1,0) OVER (ORDER BY SAL)  SUM_SAL  FROM EMP  ORDER BY SAL EMPNO EN...
Saturday, 13 June 2015

Popular Personal interview Question

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Question: What is your weakness? Ans: I concentrate on one thing at a time. Question: Reason behind leaving your last job? Ans: Looki...
Thursday, 9 October 2014

MINUS/EXCEPT in Microsoft Access

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Microsoft Access is not supporting Minus or Except. If , we want to find the difference in data between two tables we can use the below ...
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Monday, 1 September 2014

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Populate SCD3 from SCD2. SELECT * FROM ( SELECT A.SK,A.EID,A.ST_DT,A.ED_DT  FROM EMP2 A INNER JOIN (SELECT MAX(ED_DT) AS N_ED_...
Wednesday, 25 June 2014

Virtual Column in Where clause

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Question: Can we call virtual column in the where clause. Answer: Yes, we can. Description: Suppose we have the Standard EM...