How to speed up a table full scan?
671265Mar 11 2010 — edited Mar 11 2010Dear all,
Here is the case,
table t has 15,000,100 rows
SQL "select count(*) from t where b=***; " returns 15,000,055 rows.
SQL "select count(distinct a) from t where b=***;" returns 4000 rows.
How could tune SQL "select distinct a from t where b=***;" ?
Any comments will be appreciated!
Best wishes,
Satine