Limit- mysql query

felito · #1 (**permalink**) 01-11-12, 18:04

I would like to know how can i limit the output by the number of id_offers and not the number of rows. For example

Code:

  SELECT  A.id_offer, T.tags  
        		FROM offer A
        		INNER JOIN offer_has_tags Z
                ON A.id_offer = Z.offer_id_offer
                
          		INNER JOIN tags T
                ON Z.tags_id_tags = T.id_tags
                
        		WHERE state = 0 
        		ORDER BY date
        		DESC LIMIT 0, 10

output:

Code:

      id_offer 	tags
        77 	     xx 
        76 	     xx 
        76 	     xx 
        75 	     xx 
        75 	     xx 
        74 	     xx 
        74 	     xx
        73 	     xx
        73 	     xx
        72 	     xx

r937 · #2 (**permalink**) 01-11-12, 18:27

Quote:

Originally Posted by felito

I would like to know how can i limit the output by the number of id_offers and not the number of rows.

may i ask what you're going to do with the tags?

perhaps a GROUP_CONCAT of the tags for each id is feasible?

so instead of producing this --

Code:

id_offer  tags
    77       xx 
    76       xx 
    76       xx 
    75       xx 
    75       xx 
    74       xx 
    74       xx
    73       xx
    73       xx
    72       xx

the query will produce this --

Code:

id_offer  tags
    77       xx 
    76       xx,xx
    75       xx,xx
    74       xx,xx
    73       xx,xx
    72       xx

and then LIMIT will work on the summary rows, one per id

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