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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2
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1answer
728 views

How to re-assign two variables in a conditional UPDATE

Consider a simple update as SET @var1 = 20; SET @var2 = 26; UPDATE table1 SET col1=IF(@var1>50, @var1 := @var1-col4, @var1 := @var1+col5), col2=IF(@var2>50, @var2 := @var2-col6, @var2); ...
0
votes
1answer
546 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 ...
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4answers
445 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 ...
2
votes
2answers
2k views

Most efficient way to add a serial column to a huge table

What's the fastest way to add a BIGSERIAL column to a huge table (~3 Bil. rows, ~ 174Gb)? EDIT: I want the column to be incremented values for existing rows (NOT NULL). I didn't set a fillfactor ...
3
votes
1answer
366 views

A function to check if a column allows NULL

Is there a way to write an insert/update query that checks if a column allows NULLs: If it does set the column to NULL, and '' (empty string) otherwise? I would be something like: UPDATE mytable ...
3
votes
3answers
889 views

Update field with new string made from characters in existing value

field is meta_value and current value is like 01/01/2006 i want to change it to a string 20060101 so thought i could get the value and update it with the characters in the correct order. ie UPDATE ...
2
votes
1answer
987 views

I have to update all the rows of a Column in a table. Here is my query

So My tables are People: People_name(VARCHAR 100), People_id (INT, PRIMARY KEY AUTO INCREMENT) Tracks: Track_id(INT PRIMARY KEY), People_id_references (int ,Foreign key references ...
2
votes
1answer
339 views

Update ranking on table

I have two tables: mysql> desc rank ; +----------------+-------------+------+-----+---------+----------------+ | Field | Type | Null | Key | Default | Extra | ...
2
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2answers
2k views

GROUP BY two columns

I want to count two columns, but need to get the results of first column in one row. SELECT country, COUNT(*) FROM table1 GROUP BY country, type This query gives me country type COUNT(*) ...
3
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2answers
548 views

postgreSQL update set only where cast is possible and ignore error?

I have 2 columns in a PostgreSQL table. The mac_address_temp column is for migration from character type to MAC-address type: mac_address | macaddr | mac_address_temp | character ...
1
vote
1answer
673 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 ...
4
votes
2answers
4k views

Updating Multiple Rows with Data from Column A into Column B?

I have about 60,000 rows that I'm needing to update the information from column_a to column_b. For example, 60,000 customers need their arrival_time to match their departure_time. I understand that ...
2
votes
1answer
1k views

SQL Select WHERE row updated

USE [RF_WORLD] GO /****** Object: Trigger [dbo].[lastdeathtrigg] Script Date: 08/20/2012 10:52:58 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ...
7
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1answer
1k views

Direct the OUTPUT of an UPDATE statement to a local variable

I would like to do this : DECLARE @Id INT; UPDATE Logins SET SomeField = 'some value' OUTPUT @Id = Id WHERE EmailAddress = @EmailAddress -- this is a parameter of the sproc Is this even ...
0
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0answers
96 views

Being careful about additional records being added in a duplicate record merge?

We have a multi-user MS-Access 2003 database. Connecting to it using SQuirrel SQL, and the JDBC/ODBC bridge, I've managed to eek transactions of some sort out of JET by turning off autocommit. I've ...
4
votes
2answers
239 views

fast bulk incrementing in MySQL

I have one big table foobar describing a many-to-many-relation and containing millions of foo's, millions of bar's and every bar having several hundereds of foo's -> billions of rows. CREATE TABLE ...
1
vote
1answer
1k views

Why I cannot let EXPLAIN update statements?

I can imagine that it's actually more important to explain SELECT statements, but I wonder why there's no possibility to use EXPLAIN on UPDATEs/INSERTs. I may use a WHERE-statement in an UPDATE where ...
1
vote
1answer
228 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 ...
0
votes
1answer
128 views

Updating a table based on condition

I have a database having a staging_table. From this table, entries are added to other table named Profile. Whenever staging_table is updated, it checks whether all its entries are present in Profile, ...
6
votes
1answer
5k views

Trigger to UPDATE after UPDATE?

I want to make a trigger to record the time of any update as CREATE TRIGGER col_update AFTER UPDATE ON col FOR EACH ROW BEGIN UPDATE col SET updated=NOW() WHERE id=NEW.id; // or OLD.id END The ...
3
votes
1answer
535 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
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2answers
321 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
vote
1answer
978 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
271 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
249 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 ...
4
votes
2answers
6k 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 ...