query only nat empty columns in google sheet - google-sheets

Question

I exported products to google sheet from woocommerce site with wp all export and it brings me too much columns and the more columns the harder it is handle and slower to import so i have tried query thet filters out columns that have in the title the word "taxonomy" and it seems that it can work for more complicated things as well
=QUERY(FILTER(test!K2:DF9,REGEXMATCH(test!K2:DF2,"Taxonomy")=False),"SELECT *")
this is products attribute columns:
"Name _1 Value _1 Variations _1 Visible _1 Taxonomy _1"
for each attribute the number is incremented so the next attribute column looks like this:
"Name _2 Value _2 Variations _2 Visible _2 Taxonomy _2"
each possible value have these 5 columns to be able to map it with wp all import
and i have over 50 possible values * 5 = 250 columns (too much unneeded columns)
so in the case above if Value _1 column is empty
i need to filter out these columns from the QUERY
"Name _1 Value _1 Variations _1 Visible _1 Taxonomy _1"
if Value _2 column is empty
i need to filter out these columns from the QUERY
"Name _2 Value _2 Variations _2 Visible _2 Taxonomy _2"
how can i query only the coulmns thet the "Value _(any number)" column is nat empty?

Answer 1

Found simple workaround, first use this to extract the number of the not empty column to the row above.
=if(JOIN("",AX3:AX)=""=false,REGEXEXTRACT(AX2,"\d+"),"")
then filter empty cells and join with "|" delimiter so it's ready for regex
=JOIN("|",FILTER(C1:1,C1:1<>""))
and now I can use REGEX MATCH with the joined numbers that look like this 9|17|20 etc. That is placed in 'test'!A1
=FILTER('test'!I2:IS250,REGEXMATCH('test'!I2:IS2,'test'!A1))