SQL dialects reference - Wikibooks, collection of open-content textbooks

Raha mitady aide momba ny SQL ianao, dia ity no mba atoroko anao kely. Ahitanao ireo references rehetra ilaina izy ireo ary ahitanao ihany koa fampitahana. Tsara raha jerenao mihitsy raha mety.  

Link to SQL dialects reference - Wikibooks, collection of open-content textbooks

http://aam.ugpl.de/?q=en/sql_help/functions

http://sqlzoo.net/howto/source/z.dir/tip106453/postgres