Converting INSERT commands to UPDATE
I have two INSERT
commands, that are useless to me like that because the two sets of rows - the ones that are already in the table, and the ones I have as INSERT
commands - are not disjunct. Both commands insert lots of rows, and lots of values.
Therefore I get the duplicate entry error if I want to execute those lines.
Is there any easy way to 'convert' those commands into UPDATE
?
I know this sounds stupid, because why do I make INSERT
commands, if I want to UPDATE
. Just to make it a clear scenario: another developer gave me the script:)
Thanks in advance, Daniel
EDIT - problem solved
First I created a table and filled i开发者_如何学运维t up with my INSERT
commands, then I used the following REPLACE
command:
REPLACE
INTO table_1
SELECT *
FROM table_2;
This can originally be found at: How can I merge two MySQL tables?
MySQL's REPLACE
keyword does this. Simply replace the INSERT
keyword in your queries with the word REPLACE
and it should update the rows instead of inserting new ones. Please note that it will only work if you're inserting a primary key or unique key column.
You would have to rewrite them to updates by hand. If I encouter such a problem, I query for the count of certain primary key first, if none is found I insert a generic dataset and update it afterwards. By this, new data can be added and already existing data will be updated, and you don't have to differentiate between inserting new data and updating data.
For MySQL, you can use either the INSERT IGNORE
or the INSERT ... ON DUPLICATE UPDATE
syntaxes. See the MySQL reference manual
You can easily modify your queries to update duplicate rows, see INSERT ... ON DUPLICATE KEY syntax in MySQL
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