UPDATE changes the values of the specified columns in all rows that satisfy the condition. Only the columns to be modified need be mentioned in the SET clause; columns not explicitly modified retain their previous values.
0
votes
3answers
172 views
INNER JOIN Giving time out on large database
Getting time out on this script
UPDATE
uk_data AS ud
INNER JOIN
uk_pc AS up
ON ud.cat10 = up.WardCode
SET
ud.cat8 = up.Latitude,
ud.cat9 = up.Longitude;
uk_pc Table ...
4
votes
2answers
2k views
Update many rows in a table with a single statement?
What is the easiest way to update many rows in a table? I have a csv file that looks like this:
|primary_key |value|
| 1 | xyz|
| 2 | abc|
| 3 | def|
...
Rows with ...
3
votes
3answers
81 views
Backup very large table
I'm deeply sorry if this is an amateurish question, but I have to update certain values of a large table (for the sake of a presumed example, it is called 'Resource' and it is over 5M rows) and thus I ...
3
votes
1answer
285 views
Update rank on a large table
I have a mysql table that has now 12 million records and I'm trying to update a column (rank) with the following UPDATE code:
SET @r=0;
UPDATE records SET rank= @r:= (@r+1) where type = 2 ORDER BY ...
2
votes
1answer
118 views
Update ranking on table
I have two tables:
mysql> desc rank ;
+----------------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
...
1
vote
3answers
196 views
Problem with nested UPDATE queries
I cannot make an update query work. As a first step, the following one works correctly:
UPDATE Tab1
SET Tab1.a = '3'
WHERE
Tab1.id IN ( 123, 456 );
where id is the primary key of Tab1.
...
0
votes
0answers
111 views
Which update is faster using join or sequential?
My this question is in sequence of my previous question I asked.
I could write two solutions using Stored Procedure instead of trigger or nested-query .
Both use a helper function ...
