mysql - PHP "Simple" query takes massive time -


I have a question about performance, I think I am doing something wrong.

I have a table with items, and one with categories, any item can be in multiple categories. Now I want to show all those things which have not been included in any category.

The connection table contains Items_Categories (just with ID_item and ID_category )

I Created query: 

  as item ID_ item as id (items_Categories from item ID_item) Select

this works , But it is very slow it takes a few seconds, and my DB is not so big. I have around 3000 items and 200 categories.

Any better solution?

You probably can use a join and find people who have a match is not. 

  SELECT i. * Items are added to item items i.id_item = ic.ID_Item on I .ID_Item IS is null

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