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Questions tagged [update]

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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79
votes
1answer
61k 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 ...
40
votes
4answers
269k 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 ...
37
votes
2answers
45k 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 = ...
32
votes
6answers
80k 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 ...
31
votes
5answers
32k 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 ...
27
votes
4answers
21k views

Does updating a row with the same value actually update the row?

I have a performance-related question. Let's say I have a user with first name Michael. Take the following query: UPDATE users SET first_name = 'Michael' WHERE users.id = 123 Will the query actually ...
20
votes
3answers
28k 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 ...
17
votes
2answers
6k views

What's the overhead of updating all columns, even the ones that haven't changed [closed]

When it comes to updating a row, many ORM tools issue an UPDATE statement that sets every column associated to that particular entity. The advantage is that you can easily batch the update ...
16
votes
3answers
1k 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= ...
16
votes
3answers
32k 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 ...
15
votes
3answers
11k views

SQL Server : How to disable trigger for an update only for your current session?

I am working on SQL Server 2008 R2. I have a table benefit which has a AFTER INSERT, UPDATE trigger named tiu_benefit. I want to write an UPDATE statement for this table to update 1 row but I dont ...
15
votes
2answers
3k 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 ...
14
votes
2answers
39k 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(...
14
votes
1answer
455 views

Unique index updates and statistics row modification counters

Given the following table, unique clustered index, and statistics: CREATE TABLE dbo.Banana ( pk integer NOT NULL, c1 char(1) NOT NULL, c2 char(1) NOT NULL ); CREATE UNIQUE CLUSTERED ...
13
votes
1answer
22k views

Is it possible to modify an existing trigger definition in MySQL?

I am wondering if it is possible to update a trigger definition in MySQL. For example, I have a trigger T and I want to add some new functionality to it. My assumption is that I need to drop and ...
13
votes
2answers
36k 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 ...
13
votes
1answer
1k 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 ...
13
votes
1answer
46k 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 * =...
13
votes
3answers
36k views

Update a json element in json datatype

I can't figure how can I update an element in a PostgreSQL 9.3 datatype. My example: CREATE TABLE "user" ( id uuid NOT NULL, password character varying(255), profiles json, gender integer ...
13
votes
1answer
1k views

Cannot insert duplicate key row on a non-unique index?

We have encountered this strange error three times over the past few days, after being error free for 8 weeks, and I'm stumped. This is the error message: Executing the query "EXEC dbo....
12
votes
3answers
51k 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 ...
12
votes
5answers
4k 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=...
11
votes
6answers
29k 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 ...
11
votes
3answers
69k views

Use CASE to select columns in UPDATE query?

I can use CASE to choose which columns to display in a SELECT query (Postgres), like so: SELECT CASE WHEN val = 0 THEN column_x WHEN val = 1 THEN column_y ELSE 0 END AS ...
11
votes
5answers
5k 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 ...
11
votes
3answers
52k 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 ...
11
votes
2answers
5k 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 ...
11
votes
2answers
87k views

Updating multiple rows with different values in one query

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 ...
11
votes
1answer
10k 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 ...
10
votes
2answers
84k views

Update column with data from another table

I am working on complicated problem, but I will simplify it to this problem. I have two tables A [ID, column1, column2, column3] B [ID, column1, column2, column3, column4] and I want to update the ...
10
votes
1answer
328 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
1answer
8k 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 ...
9
votes
1answer
27k 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 ...
9
votes
2answers
28k 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 ...
9
votes
1answer
27k 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 (...
8
votes
2answers
2k 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(...
8
votes
2answers
119k views

Update table using values from another table in SQL Server

I have 2 table in my database. Table #1 ------------------------------------------------------------------------- | name | family | phone | email | gender | phone2 | address | birthdate | -----------...
8
votes
2answers
5k views

Update request using table alias

Executing this request: update table t1 set t1.column = 0 where t1.column2 = 1234 Getting this error: column "t1" of relation "table" does not exist This request runs fine in MySQL. Why do I ...
8
votes
1answer
13k 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 ...
8
votes
0answers
108 views

Why does my update statement update every row? [duplicate]

Problem: My final update statement should error out due to syntax and rollback the transaction, the expected error should be similar to: Msg 207, Level 16, State 1, Line 45 Invalid column name '...
7
votes
2answers
101 views

XQuery doesn't update XML data

I am trying to run the script to update an XML column: UPDATE DataImpTable SET serviceData.modify('replace value of (/SMObjInfo/CentralData/SMData/CentralSDItem/ControlData/text())[1] with "9876"') ...
7
votes
2answers
3k views

Simple SQL CTE update

I am a little stumped with this CTE update stmt: DECLARE @a TABLE (ID int, Value int); DECLARE @b TABLE (ID int, Value int); INSERT @a VALUES (1, 10), (2, 20); INSERT @b VALUES (1, 100),(2, 200); ...
7
votes
2answers
6k 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 ...
7
votes
1answer
121 views

Update Intersect hangs

We have this really weird behavior we just started experiencing with our update intersect statements. These were working fine, but now we are ingesting a pretty wide data source in terms of columns ...
7
votes
1answer
31k 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 ...
7
votes
2answers
5k 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 ...
7
votes
1answer
4k views

Update by iterating table in batches faster than whole table in PostgreSQL

I have a table with approximately one million rows. It is being used in production and I ran an UPDATE which covers ~95% of those rows. After five hours I cancelled the request because it was taking ...
7
votes
6answers
5k 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 ...
7
votes
1answer
1k 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 ...
6
votes
3answers
27k 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 ...