select substr('geek interview',rownum,1) from user_objects where rownum<=length(trim('geek interview));




can u explain the word by word meaning.




substr('geek interview',rownum,1)----here rownum value is?--------------------


trim(geek interview )gives-----------?


total query gives what

Dear Jayanth,

Trim removes trailing and leading blank spaces.
legth return the length of a string.
substr(src,p,l) :- Retruns a portion of src starting at position p and l caharacters long.
I already given explanation to rownum and rowid for your last posting.

All these are simple functions for which you can find explanation in any text book or reference material.

If you find it difficult to understand entire query at a time split it into small queries, execute each query seperately as follows and see the result.


select trim('geek interview') from dual;
select length(trim('geek interview')) from daul;
select substr('geek interview',2,1) from dual;

Then it will become easy for you to understand the output of following query.

select substr('geek interview',rownum,1) from user_objects where rownum<=length(trim('geek interview'));

Execute the above queries and find the output yourself .

Regards
Krishna

substr('geek interview',rownum,1) what itgives.


ex.
substr('jayanth',3,4);her 2nd parametr is 3.
gives' yant' right.

but in substr('geek interview',rownum,1) 2nd parametr rownum value is


dont mine i did not understand the concept of rowid, row num .can u give detail exmple for that

Dear Jayanth,

For each row returned by a query, the ROWNUM returns a number indicating the order in which Oracle selects the row from a table . The first row selected has a ROWNUM of 1, the second has 2, and so on.


For example let us suppose there are fourteen records in EMP table and you want to display first ten records from the table then you may use the following command.

Select * from emp where rownum <=10;

In this query
select substr('geek interview',rownum,1) from user_objects where rownum<=length(trim('geek interview));

Length(trim('geek interview')) returns value 14.

So it becomes becomes
select substr('geek interview',rownum,1) from user_objects where rownum<= 14;

The above query returns 14 rows.

For the first row rownum is 1
Substr('geek interview', 1, 1) retruns G.
For the second row rownum is 2
Substr('geek interview', 2, 1) retruns E and So on.

I hope now it is clear to you.

Regards
Krishna

thanks a lot

but user_objects means in that query

Trim removes trailing and leading blank spaces.what it means
Length(trim('geek interview')) gives ---------------
length('geek interview') gives what

USER_OBJECTS describes all objects owned by the current user
objects are tables,views,tiggers,packages,sequences,procedures,functions

the trim function removes all specified characters either from the beginning or the ending of a string

from this example u can find the difference of Length(trim('geek interview'))

select Length(trim('geek interview')) from dual returns 14

select length('geek interview') from dual; returns 14

but if i give space in beginning of geek interview then

select Length(trim(' geek interview')) from dual returns 14

but select Length(' geek interview') from dual return 15