Guy M. Lohman Do semantically equivalent SQL queries perform differently? 225-226 ICDE86/P225.pdf 1986 ICDE db/conf/icde/icde86.html#Lohman86 conf/icde/86 journals/cacm/AstrahanC75 conf/vldb/LuC85 journals/ibmsj/ChengLSW84 conf/vldb/LohmanDHKS84 books/sp/kimrb85/LohmanMHDLSW85 journals/tods/MackertL89 conf/sigmod/SelingerACLP79 ... journals/tods/WongY76