SELECT *, (SELECT bs_type FROM bookshelf WHERE bs_mem_id='' AND bs_prd_id=prd.prd_id) as onshelf, (SELECT 1 FROM bookshelf WHERE bs_mem_id='' AND bs_prd_id=prd.prd_parent) as gotparent, (SELECT CONCAT(p.prd_id,',',p.prd_cover) FROM prd p WHERE p.prd_parent = prd.prd_id) as hasChild, IF(prd.prd_parent>0,(SELECT p.prd_cover FROM prd p WHERE p.prd_id = prd.prd_parent),'') as parent_cover FROM prd WHERE prd_id=?
0 => 21000
1 => 1242
2 => Subquery returns more than 1 row