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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30 views

Create a new table (multiple columns) by selecting random values from an existing table

I am stuck on the following task (PostgreSQL 9.3). Let's say we have the following table1 (which has 10k rows): table1: id 754 800 330 4 59 My goal is to create another table2 with two columns ...
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1answer
85 views

scenario to update or insert big amount of data

I try to find the best scenario to update or insert 1 million contacts in my postgres database. My actual scenario is: read contacts 1000 per 1000 and try to insert multiple rows with one request ...
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1answer
519 views

Oracle 10g: Optimizing an update query that uses a subquery

I have the following query within a stored procedure, and I've been trying to improve its performance to no avail. UPDATE TBL_REPORTING REP SET (REP.ISSUER_ID, REP.ISSUER_NAME ) = ( ...
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32 views

MySQL ON DUPLICATE KEY UPDATE performance issue

We have a table with over 200k rows. Every row belongs to a category, there are almost 50k rows per category. What is the best way to update all rows of that category? We are using a script like ...
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1answer
36 views

Update previous value field

I inherited a database that has multiple tables that contain some form of an object ID, a date, and a value. The metrics depend on comparing the current value on any given date to the previous value ...
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1answer
57 views

phpmyadmin not working after mysql update

i followed this guide to update my mysql form 5.1 to 5.5. After lots and lots of command and headache, i was able to upgrade mysql. i checked the version via terminal. But now there is another ...
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1answer
68 views

Very slow update with subquery (different tables)

I run this query to update "domains" table based on "log" table: UPDATE domains SET domains.mx_collected = 0 WHERE domains.domain IN (SELECT log.mail as domain_name FROM log WHERE `time` >= ...
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29 views

How does partitioning and the lack of a primary key affect ON DUPLICATE KEY UPDATE

Consider a table with the following columns: phone BIGINT NOT NULL PRIMARY KEY, name VARCHAR(64), state VARCHAR(64) We would like to partition the table on state, however that would require ...
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33 views

ON DUPLICATE KEY UPDATE faster than UPDATE

I have a table with about 17 million rows: mysql> describe humans_we_respect; ...
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190 views

Best Practice to update columnstore indexed tables

I have a table with aprox. 22 Bn rows, for each month I have made one partition that and each partition has two data files. I created the columnstore index on this table and the performance ...
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0answers
13 views

How do I stop views (large data sets) from freezing my database

I am working with tables that contain upwards of 200,000 rows. My boss wants to use views that refer to other views in order to have things be more automated. The problem is that the MySQL server ...
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18 views

Oracle after insert trigger vs update performance in plsql block

I want to know whether an after insert trigger is better than an insertion statement followed by update statement in plsql block.
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26 views

Access 2013 compare changes made to table

I am currently working on an Access 2013 database and trying to find the best solution to a problem I am having creating it (I am fairly new to databases so bear with me). Situation: Data is imported ...
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66 views

How do I perform a batch update on the first n matching rows?

I need to perform a large number of updates at the same time. Each update needs to only affect up to a specific number of rows even though the WHERE clause might match to many more rows. So far, I'm ...
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54 views

Multiple update of records in the same table

I have an update query. E.g. UPDATE table SET name = ? WHERE id = ? Now I have all the relevant ids collected. What I am doing is looping over the ids and execute the update query for each one. E.g ...
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0answers
15 views

How to categorize pairs of tags?

I have a table containing pairs of tags (say html tags) such as id tag tag_match 1 <div class="first"> 1 2 <div class="second"> 2 3 </div> ...
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58 views

How to retrieve pkey value in mysql/python on duplicate key update

I'm currently using _mysql library in python. it uses pkey(int, auto increment) value that's created when inserting data using function conn.insert_id() This is how the query is made. INSERT INTO ...
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434 views

SQLite UPDATE two tables from VIEW or TEMPORARY TABLE

Here is the query that doesn't compile just to show how it should look like. But since I can't do Multiple table UPDATE's. This fake query should be able to run the inner UPDATE's for both tables if ...
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55 views

Inserting and updating on same table

I am currently working on a database that aims to provide information regarding the amount of time people stay in a company's car-park premises. This is done using a table called "tbl_stay" which has ...
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154 views

Alternatives for UPDATE statement Oracle 11g

I'm currently using Oracle 11g and let's say I have a table with the following columns (more or less) Table1 ID varchar(64) Status int(1) Transaction_date date tons of other columns And this ...
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129 views

SQL queries are very slow

I have noticed that my queries are getting slower. Some update queries take about 48-50 seconds. Here's how it looks: [root@db-1 ~]# tail /var/lib/mysql/mysql-slow.log # Time: 131113 17:09:48 # ...
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42 views

Is it better performance wise to check if a field needs update if you know the record does

In the queries we use all the records in one table that has data which needs to be placed in a another system had a Insert, Update and Delete flags (i, u, d being 1 in the record), this way we can ...
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81 views

mysql table not updating no errors

i am using mysql 5.2.44 CE revision 9933 i have a table in which i am trying to update a few columns of the rows i am not using queries, just doing it using the edit table UI provided in the ...
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99 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 ...