MySQL数据库中的join的实际应用演示
数示复制cost = outer access cost + (inner access cost * outer cardinality) 1.
数示复制cost = outer access cost + (inner access cost * outer cardinality) 1.
数示复制cost = outer access cost + (inner access cost * outer cardinality) 1.
数示复制cost = outer access cost + (inner access cost * outer cardinality) 1.