Re: Union query
Girish Kagrana wrote:
> I have two queries as follows
>
> query-1
> -------
>
> select tabid,"from_1st_select" from systables where tabid < 4
> union
> select tabid,"from_2nd_select" from systables where tabid < 4>
> query-1-output
> --------------
> tabid (constant)
>
> 1 from_1st_select
> 1 from_2nd_select
> 2 from_1st_select
> 2 from_2nd_select
> 3 from_1st_select
> 3 from_2nd_select
>
> query-2
> -------
>
> select "from_1st_select" from systables where tabid < 4
> union
> select "from_2nd_select" from systables where tabid < 4
>
> query-2-output
> --------------
>
> (constant)
>
> from_1st_select
> from_2nd_select
>
> Question : the 1st query returns 6 rows, that is ok,
> why 2nd query is returning 2 rows, why not 6 rows
A union select removes all duplicate rows...
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