select count(*) from b_tokerclue tc WHERE CASE '6'WHEN '0' THEN1=1WHEN '1' THENtc.CreateTime > '2018-01-01'WHEN '2' THENtc.CreateTime < '2018-01-10'WHEN '3' THENtc.TheFirstVisitDate>'2018-01-01'WHEN '4' THENtc.TheFirstVisitDate<'2018-01-10'WHEN '5' THEN1>2WHEN '6' THENtc.CreateTime>'2018-01-01' and tc.CreateTime<'2018-01-10'WHEN '7' THENtc.TheFirstVisitDate>'2018-01-01' and tc.TheFirstVisitDate<'2018-01-10'ELSE1=1END;其中CreateTime已經建立了索引，但是查看執行計劃為全盤掃碼，請問這種情況怎么解決。謝謝各位大神了