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.

learn more… | top users | synonyms (1)

26
votes
1answer
11k views

Postgres UPDATE … LIMIT 1

I have a Postgres database which contains details on clusters of servers, such as server status ('active', 'standby' etc). Active servers at any time may need to fail over to a standby, and I don't ...
22
votes
2answers
16k views

Optimizing bulk update performance in PostgreSQL

Using PG 9.1 on Ubuntu 12.04. It currently takes up to 24h for us to run a large set of UPDATE statements on a database, which are of the form: UPDATE table SET field1 = constant1, field2 = ...
15
votes
3answers
433 views

Slow update on large table with subquery

With SourceTable having >15MM records and Bad_Phrase having >3K records, the following query takes almost 10 hours to run on SQL Server 2005 SP4. UPDATE [SourceTable] SET Bad_Count= ...
15
votes
3answers
14k views

How to optimization database for heavy I/O from updates (software and hardware)

The situation I have a postgresql 9.2 database which is quite heavily updated all the time. The system is hence I/O bound, and I'm currently considering making another upgrade, I just need some ...
13
votes
5answers
118k views

How to update one table based on another table's values on the fly?

I have a table in the name of ips as below: CREATE TABLE `ips` ( `id` int(10) unsigned NOT NULL DEFAULT '0', `begin_ip_num` int(11) unsigned DEFAULT NULL, `end_ip_num` int(11) unsigned DEFAULT ...
13
votes
4answers
3k views

UPDATE performance where no data changes

If I have an UPDATE statement that does not actually change any data (because the data is already in the updated state). Is there any performance benefit in putting a check in the WHERE clause to ...
11
votes
2answers
201 views

PostgreSQL Recursive Descendant Depth

I need to calculate the depth of a descendant from it's ancestor. When a record has object_id = parent_id = ancestor_id, it is considered a root node (the ancestor). I have been trying to get a WITH ...
10
votes
5answers
683 views

Why does this UPDATE fail with a unique key constraint violation?

I'm an "accidental" DBA, relatively inexperienced and baffled by this problem. Running MS SQL Server 2012. The problem is with this UPDATE statement: UPDATE dbo.tAccts SET Ticket ...
10
votes
1answer
508 views

Do databases make a delete and an insert when having to update rows?

So today a professor told us that when the database has to make an update, internally (at low level) it makes a delete and then an insert with the updated fields. He then said that this is something ...
10
votes
2answers
11k views

How can I update a json element in postgresql json datatype

I can't figure how can I update an element in a postgresql 9.3 datatype. My exemple the db CREATE TABLE "user" ( id uuid NOT NULL, password character varying(255), profiles json, gender ...
10
votes
1answer
271 views

Why is my SQL Server query behaving differently on UPDATE than on SELECT?

I've written a SQL Server query that updates records to have a sequential number after partitioning on a field. When I run it as a SELECT statement, everything looks great: DECLARE @RunDetailID INT = ...
9
votes
3answers
759 views

Update all rows

I want to know the most efficient manner to update every row in an extremely large Oracle table for a single column. For example: update mytable set mycolumn=null; or: update mytable set mycolumn=...
8
votes
6answers
852 views

Switching values in a column with one update statement

You find that an error in a system has been incorrectly naming men (M) as women (W) and vice versa in the database. The columns only allows for one character. Without using any temp tables, write one ...
8
votes
2answers
18k 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 ...
8
votes
1answer
20k views

On duplicate key do nothing

I am inserting into the following table using LuaSQL with PtokaX API. CREATE TABLE `requests` ( `id` INT(10) UNSIGNED NOT NULL AUTO_INCREMENT, `ctg` VARCHAR(15) NOT NULL, `msg` VARCHAR(...
8
votes
1answer
20k 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 ...
7
votes
2answers
307 views

8k row overflow error when updating row of size 5k

I'm trying to update a target table which has one row of size 5k to a row of size 5k also. Since it's one row it's easy to know the row actual size: select * from sys.dm_db_index_physical_stats(...
7
votes
3answers
19k views

Cascade primary key update to all referencing foreign keys

Is it possible to update a primary key column value with cascading the update among all the foreign keys referencing it ? # EDIT 1: When I run followinq query select * from sys.foreign_keys where ...
7
votes
1answer
3k 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 ...
7
votes
2answers
1k views

Effect of an index on update statements where update column is not in an index

I constantly see people say that indexes slow down update, delete and insert. This is used as a blanket statement, as if it is an absolute. While tuning my database to improve performance, I keep ...
7
votes
5answers
1k views

How to update 10 million+ rows in MySQL single table as Fast as possible?

Using MySQL 5.6 with InnoDB storage engine for most of the tables. InnoDB buffer pool size is 15 GB and Innodb DB + indexes are around 10 GB. Server has 32GB RAM and is running Cent OS 7 x64. I have ...
6
votes
3answers
15k 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 ...
6
votes
3answers
289 views

Updating a view on multiple joined tables

Since MSDN does not say much, what happens exactly if I execute the following query? update claims set status='Awaiting Auth.' where status = 'Approved' Can I use the ClaimStatusName column of the ...
6
votes
2answers
13k 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 (...
6
votes
1answer
11k views

UPDATE table based on the same table

I have a table with product descriptions, and each product description has a product_id and a language_id. What I want to do is update all of the fields with a language_id of 2 to be equal to the same ...
6
votes
1answer
2k views

Optimizing concurrent updates in Postgres

I'm running concurrent Postgres queries like this: UPDATE foo SET bar = bar + 1 WHERE baz = 1234 Each query affects the fixed K number of rows, and I can't find a way to enforce the order in which ...
6
votes
1answer
6k views

How to remove known elements from a JSON[] array in PostgreSQL?

I'm facing an issue regarding using the JSON data type in PostgreSQL. I try to achieve storing a Java model denormalized in the DB. The model features lists of complex objects. Thus, I decided to ...
6
votes
1answer
17k views

Update all columns from another table

I need to update a table from another one, and I need to update all columns. Besides listing every column in the SET clause, is there a way to update them all at once? Like this: update tableA set * =...
6
votes
1answer
276 views

Locking in Postgres for UPDATE / INSERT combination

I have two tables. One is a log table; another contains, essentially, coupon codes that can only be used once. The user needs to be able to redeem a coupon, which will insert a row into the log table ...
6
votes
1answer
15k views

What's the most efficient way to batch UPDATE queries in MySQL?

I'm writing an application that needs to flush out a large number of updates to the database for an extended period of time, and I've gotten stuck at how to optimize the query. Currently I'm using ...
6
votes
2answers
558 views

Is this update, select combination query thread safe?

I have a table called seats, which has a schema like this id,taken For each user, I take a random untaken id and assign to that user, here for simplicity say, I make taken =1. The query I am ...
6
votes
1answer
409 views

.WRITE clause performance optimization

I have found that you can do high performance updates on varchar(max),nvarchar(max),varbinary(max) columns using the .WRITE clause(example here and here). Unfortunately, there is nothing mentioned ...
5
votes
4answers
539 views

How can I avoid repeating the same condition in a “when matched then update” clause?

I want to merge one table into another. I need to apply conditional logic in my WHEN MATCHED clause, which would ideally be done like this: MERGE INTO ATable AS a USING BTable AS b ON a.ID = b.ID ...
5
votes
2answers
1k views

Insert RECORD into a table in a trigger function

I would like to insert a RECORD data type variable (NEW variable) into a table in a trigger. What would the SQL look like? The following attempts were unsuccessful: EXECUTE 'INSERT INTO my_table ...
5
votes
3answers
8k views

Update statement is giving an invalid column name error, even though the column exists

I have a temporary table created at the beginning of this stored procedure. It is created successfully and can be selected from and inserted to. Here is the create statement CREATE TABLE #...
5
votes
2answers
5k views

Adding a sequence number to existing rows

I have a table with an OrderSequence column. The schema looks roughly like this: id Name OrderSequence I have an array of ids ["1", "2", "3", "4"] from an application, and I want to set the ...
5
votes
1answer
24k views

MYSQL - UPDATING multiple rows with different values in one query (for dummies)

I am trying to understand how to UPDATE multiple rows with different values and I just don't get it. The solution is everywhere but to me it looks difficult to understand. For instance, two updates ...
5
votes
6answers
3k views

Backup very large table

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 have to make a backup before performing the changes. We ...
5
votes
1answer
16k views

Oracle: Non key-preserved table should be

I'm getting "ORA-01779: cannot modify a column which maps to a non key-preserved table" when I try to update a join. I've searched around the site and found a lot of advice on what key-preserved ...
4
votes
2answers
17k 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 ...
4
votes
2answers
421 views

Adding hstore entries to an uninitialized (NULL) column

I got bitten by this "feature" recently. If your hstore column is uninitialized and you start adding entries to it, they are all silently swallowed without error. Is this expected? create table ...
4
votes
1answer
992 views

MySQL 1175 Error While Using Primary Keys

What would cause the error 1175 that starts out with: You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column.... The problem I have is that I did include ...
4
votes
1answer
2k views

Update to session table slow

I have a number of websites with session tables on a web server, these are used by Joomla CMS and Symfony framework systems. With slow_query_log=0.6, the update queries for the session tables come up ...
4
votes
1answer
87 views

Should a table be split if only a particular column gets updates?

I have a table in my MySQL 5.7 database, which has 9 columns. One column is an AUTO INCREMENT PRIMARY KEY, where as the other 6 contain some data, which isn't going to be updated in a year. Now, the ...
4
votes
2answers
209 views

Help with tricky update statement

I've tried writting this update statement every possible way I can think of but I either wind up producing invalid results or run into a syntax barrier. I have two table variables: DECLARE @...
4
votes
2answers
564 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 `...
4
votes
1answer
20 views

Sort table rows and save the row numbers using UPDATE

I have Postgres 9.5 with a table movimientos that has the following data: | id | concepto | movimiento | numero | orden | | 1 | AJUSTE 1 | 2542 | 0 | 2 | | 2 | APERTURA | 12541 |...
4
votes
1answer
1k 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
512 views

ON DUPLICATE KEY UPDATE faster than UPDATE

I have a table with about 17 million rows: mysql> describe humans_we_respect; +---------------------+-------------------------------------------------------------------------+------+-----+---------...
4
votes
1answer
523 views

Oracle UPDATE followed by SELECT in LinqPad

I'm trying to UPDATE values in an Oracle database table (of salary information) that has no row IDs or a primary key. I'm writing these statements in LinqPad. This syntax should work just fine in ...