1
vote
1answer
194 views

What is a good way to query data stored in multiple identical tables split by date/time

I have a 3rd party piece of software which records data samples from industrial equipment. This data logging software stores data in sample data tables with approximately one day's worth of samples ...
2
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2answers
1k views

Is there any way to speed up a query with 3x UNION on the same large table?

Assuming that the following query is legitimate and executes successfully, is there any way to speed it up? SELECT foo from T1 --T1 is a huge (>5e6 rows) table with no indexes UNION SELECT bar ...
2
votes
1answer
2k views

Dealing with NULL values and EMPTY strings in UNION of two tables

I want return records from two database tables when a record differs in at least one of the fields. I have written a query for it using the UNION operator. It is working absolutely fine. However, I ...