Re: ROWNUM. can anybody clarify this to me.

Singapore Airlines Ltd (engsys_at_merlion.singnet.com.sg) wrote:
: HI,
 

: I have some basic doubts with the usage of ROWNUM.
 

: I generally used to append a condition
: WHERE rownum = 1
: for the SQL statements that check for the existence of a record.
 

: Does this stmt get all the records that satisfy the condition before
: rownum = 1 and then use this condition or
: the first instance itself it gets only one record ?
 

: Thanks for clarifying this to me.
 

: laxmi.

Hi Laxmi,

A Rownum = 1 condition will scan all rows and then return the first row. Rownums are assigned only at row retrieval. (And before the rows are ordered)

Hope this answers your question.

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Kannan 
Email: skannan_at_fs.com
Mastech Systems Corporation

The above are my own comments and opinion. They do not purport that of 
anybody else.
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