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.

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3
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1answer
877 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 ...
1
vote
1answer
271 views

extremely slow MyISAM slave updates

I have 2 slaves and one is working as expected. The other slave is extermely slow while executing the "update" statements. The insert and deletes are fast. I used "check table tbl_name" to see if any ...
1
vote
2answers
526 views

Way to update many (>3000) records with unique data, using a character limited web form

Okay, as you can probably tell from the last part of the title, this is a non-ideal situation. I'm using a piece of industry-specific web-interface software that I guarantee no one has ever heard of, ...
1
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4answers
531 views

Performance degradation while updating tables having 10s of millions of records

I want to update tables ( my be 20-30 ) having 10s of millions of records each. The problem is that it is taking too much time for the update process and also at that time CPU usage also goes very ...
1
vote
1answer
2k views

Find last (max) value according to TimeStamp using update method

I have task to find values of integer according to last (max) of timestamp (datetime) value. Because it is so complicated query I am consindering this way to find last value something like this ...
1
vote
1answer
309 views

What can cause an UPDATE statement to execute endless? [closed]

I have a stored-procedure which is executed at 7 o'clock in the morning that updates the database because new records were imported at night. Today it started but never endet. So i've tried to run ...
3
votes
1answer
372 views

See actual results of SQL UPDATE command

Is there a way to get the actual results of SQL UPDATE command (ie the table rows themselves), not just get the number of rows (other than by converting the UPDATE command to a SELECT)? I'm using ...
1
vote
1answer
882 views

How should I update ID field values for all records based on previous values?

I need a SQL query that can update ID fields for all records in a table from their previous values to a new value based on that previous value. For example, if the ID is 1, I want to change it to ...
5
votes
2answers
10k 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 ...
5
votes
3answers
7k views

Oracle 10g: Properly using ora_rowscn to detect table row changes (ie, inserts, updates, deletes)

Some research into checking when a table's records were last updated, modified, or deleted has lead me to the pseudo column known as ora_rowscn. First, I do this: select max(ora_rowscn) from ...