1
vote
1answer
84 views

How to use LOW_PRIORITY for heavy queries?

I have scheduled heavy UPDATE queries at administrator level, and since they are heavy UPDATEs with multiple JOINs, consume a huge amount of resources. I do not want them to stop end users from ...
1
vote
2answers
76 views

MySQL (InnoDB) UPDATE SET performance with value in WHERE AND clause

If an UPDATE query is performed where the values being SET are also part of the WHERE clause, in the form of an additional AND statement on the column being set's value, is there a significant ...
1
vote
1answer
84 views

How to UPDATE a table for the level of parents in a column?

I have a table with internal parents as id parent parent_level 1 NULL 1 2 1 2 3 1 2 4 3 3 where parent has a FK to id. How can I update the table ...
0
votes
0answers
21 views

How to handle constant update of geo spacial lat\long update by an web service?

I have a table which contains person details and their current geo-spacial lat\long. I am using default engine as innoDB Lat\long will be updated constantly through web service. When the user hits ...
0
votes
1answer
548 views

How to UPDATE a column to SET previous row value to NULL cells?

I have a table as id value 1 music 2 3 movie 4 5 6 book 7 8 Some values are missing, and I want to assign the value of previous row to produce id value 1 music 2 music 3 movie 4 ...
3
votes
2answers
383 views

Should I use select count(*) for counting records or having a field like comments_no for tables like post, comments?

In my recent project which is about social networking for an Asian country, I'm in doubt whether I use the below SQL statement for counting records: SELECT COUNT(id) shareLikeNo FROM ...