第1个回答 2011-10-13
/*左外联接*/
SELECT DISTINCT v.vend_id,p.prod_name
FROM vendors AS v
LEFT OUTER JOIN products AS P
ON v.vend_id=p.prod_id
AND p.prod_price>30;
/*右外联接*/
SELECT DISTINCT v.vend_id,vend_name,vend_city,p.prod_name,p.prod_id,p.prod_price
FROM vendors AS v
RIGHT OUTER JOIN products AS P
ON v.vend_id=p.prod_id
AND p.prod_price>30;
/* 内联接 */
SELECT DISTINCT v.vend_id,p.prod_name
FROM vendors AS v
INNER JOIN products AS P
ON v.vend_id=p.prod_id
AND p.prod_price>30;
/*自然联接《外联接》*/
SELECT DISTINCT v.vend_id,p.prod_name
FROM vendors AS v ,products AS p
WHERE v.vend_id=p.prod_id
AND p.prod_price>30;
就这些 看你能看懂不?
至于那交叉联接就木知了。。本回答被提问者采纳