Why does MySQL-SELECT query take too long?

Why does MySQL-SELECT query take too long?

Check the query more than once. The first run may be too long since the data should be read from the disk into the memory. When you’re running query first time the data is still not in innodb buffer and has to be read from the disk.

How to optimize a query in MySQL?

If you have access to SQL Server, highlight your complete query in SQL server, and click + L This will show the query execution plan. Optimize the query based on these results; if for example you see table scans then an index may assist. Write queries that do not use the term distinct. Do not order results if the order is unimportant.

How can I speed up mysql query time?

Google’s powerful servers are designed to scan through billions of SQL entries, for example when a Google search is performed. As long as there are no errors being returned, the above two services will help to dramatically speed up your query time. I hope I could help!

When to not order results in MySQL Query?

Do not order results if the order is unimportant. In your sample the complicated last set of order-by is very expensive.

How long does it take to select a table in SQL?

SELECT or SELECT INTO it takes up to 30 seconds. The table is more like a data copy of a view, for performance reasons which gets truncated and filled with the data from time to time. So my SQL looks like:

How long does it take to truncate select into SQL?

The second time executing the Truncate-INSERT INTO/SELECT INTO sql takes less than a second (until I clear all caches). The execution plans look the same, except for the Table Insert which has a cost of 90%. Also tried to get rid of any implicit conversions but that didnt help either.

How long does it take to join a table in SQL?

After joining 12 tables, there was no significant change in query execution time. By the time I had joined the 13th table the execution time jumped to a 1 second; 14th table 4 seconds, 15th table 20 s, 16th 90 seconds. Keijro’s suggestion to use a correlated subqueries instead of joins e.g.