索引失败的问题

Question

select count(*) from b_tokerclue tc WHERE CASE '6'
WHEN '0' THEN
1=1
WHEN '1' THEN
tc.CreateTime > '2018-01-01'
WHEN '2' THEN
tc.CreateTime < '2018-01-10'
WHEN '3' THEN
tc.TheFirstVisitDate>'2018-01-01'
WHEN '4' THEN
tc.TheFirstVisitDate<'2018-01-10'
WHEN '5' THEN
1>2
WHEN '6' THEN
tc.CreateTime>'2018-01-01' and tc.CreateTime<'2018-01-10'
WHEN '7' THEN
tc.TheFirstVisitDate>'2018-01-01' and tc.TheFirstVisitDate<'2018-01-10'
ELSE
1=1
END;

其中CreateTime已经建立了索引，但是查看执行计划为全盘扫码，请问这种情况怎么解决。谢谢各位大神了

Answer 1

建一个既包含 CreateTime 又包含 TheFirstVisitDate 的索引