Find Rows Without Match in 2nd Table, and Select Rows that Only Occur Once in 1st

Databases
1

Here is the mysql query I’m using to see which rows in our “tags” table have no matching row in our “taginfo” table.

SELECT *
FROM tags
WHERE snub NOT
IN (

SELECT snub
FROM taginfo
)

Now, I want to take this query a step further. I’m hoping to select not only the rows in the “tags” table where the “snub” column has no match, but I want to select the rows that only occur once. For instance:

list of “snub” variables in the “tags” table

comedy
romance
actor name
actor name
romance
foreign

So, in this case, it would select rows with comedy and foreign as the snub, since they only appear once.

I can’t figure out how to achieve this. (my final goal is to delete all rows that have single instance not matching).

All feedback appreciated!
Cheers
Ryan

2

You can do it like this,for example:
SELECT * FROM tags GROUP BY snub HAVING COUNT(snub)=1;

3

I know that query and have been trying to apply that to the multi-table one above, but without success.

4

Actually, that combo worked. I thought I already attempted this, but it worked this time around:

SELECT *
FROM tags
WHERE snub NOT
IN (

SELECT snub
FROM taginfo
)
GROUP BY snub
HAVING COUNT( snub ) =1
LIMIT 0 , 30