I have a situation where I have three tables: tblContacts and tblCategories in a many-to-many relationship joined through tblContactCategories (my join table). Lets say that I want to search my database for all contacts that have the categories "Student" and "Father". What is the best way to do this? Also, I don't want limited to just two categories. I had thought of using a subquery, but having more than two categories makes this tricky to be able to figure out. I have created some vba functions to which I pass the current contactID and the category that I want to check if they have that category and then I just put two of those in my WHERE clause, but I'm not sure that I like that option as I will be running this against 20,000+ records with each record having potentially four function calls. I'm just looking for the best method. The more ideas the better.
The way I usually handle something like this is - SELECT IDField
-
FROM tableName
-
WHERE Category IN ('a', 'b')
-
GROUP BY IDField
-
HAVING COUNT(*) >= 2
You can then join this to another table to pull the rest of the information you need.
6  852 
The way I usually handle something like this is - SELECT IDField
-
FROM tableName
-
WHERE Category IN ('a', 'b')
-
GROUP BY IDField
-
HAVING COUNT(*) >= 2
You can then join this to another table to pull the rest of the information you need.
That is exactly what I was looking for. Thank you so much Rabbit.
You're quite welcome. If you want to make it dynamic, you might have to use some VBA. Off the top of my head, I'm thinking a LIKE comparison against a delimited string with all the options you're looking for and a call to VBA to return the number of options in the string for the COUNT(*) filter.
Found a way to do it dynamically without VBA. Assuming you have a comma delimited string of the values you're querying for, you could use this: - SELECT IDField
-
FROM TableName
-
WHERE (',' & Forms!Form3!Text2 & ',') Like ('*,' & Category & ',*')
-
GROUP BY IDField
-
HAVING COUNT(*)=(Len(Forms!Form3!Text2) - Len(Replace(Forms!Form3!Text2, ',', '')) + 1);
Thats even better. You are a genious! Thanks again rabbit.
NeoPa 32,556
Expert Mod 16PB
He's such a smart-arse really. Isn't he?
Lucky we have him here with us and not going to waste.
Nice one again Rabbit :-)
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