select c from A
where (a1 = '1' or a2 = '1' or a3 = '1') and (b1 = '2' or b2 = '2' or b3= '1') and c = '3'
请问如何对字段进行索引,以及对语句优化,提高运行效率
...全文
2458打赏收藏
SQL语句优化,索引
表A 字段 a1 字段 a2 字段 a3 字段 b1 字段 b2 字段 b3 字段 c select c from A where (a1 = '1' or a2 = '1' or a3 = '1') and (b1 = '2' or b2 = '2' or b3= '1') and c = '3' 请问如何对字段进行索引,以及对语句优化,提高运行效率