Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
If I have 8 boolean values in a record and those 8 values are always used when doing a query against the table and the data in the table is static (read-only), is it faster to get matching records by indexing and querying against a one byte field like binary(1) or is it better to have 8 separate bit columns with all 8 added to an index?
Indexes on single bit field will be basically useless. A bit has terrible selectivity, 0 or 1, and will be likely disregarded by the optimizer. 8 indexes on 8 bit fields are going to be 8 indexes disregarded by the optimizer.
An index on a byte column is only slightly more selective, with 256 distinct values. But if you are seeking individual bit patterns, like ‘is bit 3 on’, then there are no way to express this as a individual value to seek nor as a range.
Conclusion is that no matter what you try, you will end up with a table scan anyway.
So better explain what is your problem, not your solution, and perhaps we can think at something more efficient.