Searching array for multiple items

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

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

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På onsdag 25. januar 2017 kl. 09:47:56, skrev Thomas Kellerer <
spam_eater@gmx.net <mailto: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.
 
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