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Thread: [GENERAL] Searching array for multiple items

[GENERAL] Searching array for multiple items

From
Alex Magnum
Date:
Hi,
I can search an array with 1 = ANY('{1,3,4,7}'::int[])

I need to check for one or multiple items in the array.

e.g. '1,7,3'  = ANY('{1,3,4,7}'::int[]

I do need to check if
a) all items exist in the array
b) at least one item exists in the array

Is there a an operator that allows me to do these two?
Does the order of left and right side matter?
Right now I have a small function but I guess there is a more efficient way.

Thanks for any help.

A


Re: [GENERAL] Searching array for multiple items

From
Oleg Bartunov
Date:


On Wed, Jan 25, 2017 at 11:29 AM, Alex Magnum <magnum11200@gmail.com> wrote:
Hi,
I can search an array with 1 = ANY('{1,3,4,7}'::int[])

I need to check for one or multiple items in the array.

e.g. '1,7,3'  = ANY('{1,3,4,7}'::int[]

I do need to check if
a) all items exist in the array
b) at least one item exists in the array

Is there a an operator that allows me to do these two?
Does the order of left and right side matter?
Right now I have a small function but I guess there is a more efficient way.

Look on our contrib/intarray
 

Thanks for any help.

A



Re: [GENERAL] Searching array for multiple items

From
Thomas Kellerer
Date:
Alex Magnum schrieb am 25.01.2017 um 09:29:
> I can search an array with 1 = ANY('{1,3,4,7}'::int[])
>
> I need to check for one or multiple items in the array.
>
> e.g.'1,7,3'  = ANY('{1,3,4,7}'::int[]
>
> I do need to check if
> a) all items exist in the array

You can use the contains (or is contained) operator for that:

   array[1,7,3] <@ array[1,3,4,7] is true

   array[1,7,10] <@ array[1,3,4,7] is false

> b) at least one item exists in the array

You can use the "overlaps" operator:

   array[1,7,3] && array[1,3,4,7] returns true

   array[10,11] && array[1,3,4,7] returns false

> Does the order of left and right side matter?

For the contains or (is contained) operator the order matters, for the overlaps operator it does not.

For more details see https://www.postgresql.org/docs/current/static/functions-array.html

Thomas

Re: [GENERAL] Searching array for multiple items

From
Andreas Joseph Krogh
Date:
På onsdag 25. januar 2017 kl. 09:47:56, skrev Thomas Kellerer <spam_eater@gmx.net>:
Alex Magnum schrieb am 25.01.2017 um 09:29:
> I can search an array with 1 = ANY('{1,3,4,7}'::int[])
>
> I need to check for one or multiple items in the array.
>
> e.g.'1,7,3'  = ANY('{1,3,4,7}'::int[]
>
> I do need to check if
> a) all items exist in the array

You can use the contains (or is contained) operator for that:

   array[1,7,3] <@ array[1,3,4,7] is true

   array[1,7,10] <@ array[1,3,4,7] is false

> b) at least one item exists in the array

You can use the "overlaps" operator:

   array[1,7,3] && array[1,3,4,7] returns true

   array[10,11] && array[1,3,4,7] returns false

> Does the order of left and right side matter?

For the contains or (is contained) operator the order matters, for the overlaps operator it does not.

For more details see https://www.postgresql.org/docs/current/static/functions-array.html

Thomas
 
Can you elaborate on index-usage? Ie. will the suggested queries above utilize idexes (gist?). If so, can you give an example with definition of index and explain-plan?
 
It would be interesting to see how this performs vs. contrib/intarray.
 
Thanks.
 
--
Andreas Joseph Krogh
CTO / Partner - Visena AS
Mobile: +47 909 56 963
 
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