Tuning: Min and Max in same query

Please read this article.

Karen explains why having min and max in the same query impacts performance and how to tackle the same.

Index usage

What do you think? Will an index be used in these cases?

1. Table returns 2,500,000 (2.5 million) records from a table having 10,000,000 rows (10 million).

2. You use a value !=’45′ condition in your where clause. ( Value column is indexed)

3. You say Value=’%ABC’ condition in where clause (value column is indexed)

4. You say Value=’ABC%’ condition in where clause (value column is indexed)

5. Where Value IS NULL (value column is indexed)

6. Where Value IS NOT NULL (value column is indexed)

In all these cases, do you think the index will be used or not?

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