Answer by ThomasRushton
Your index is a composite index, made up of the three fields. Because the first `select` is only searching on the `ch` field, which isn't the first field in the index definition, the engine is having...
View ArticleAnswer by Cyborg
Since your index key is in the order (ID,CH, NA), anything that searches ID,CH or ID,NA (in any order) may result in an index seek (only if your query result in few rows, if most of the rows needs to...
View Article
More Pages to Explore .....
