Mysql on duplicate key update + sub query
Using the answer from this question: Need MySQL INSERT - SELECT query for tables with millions of records
new_table
* date
* record_id (pk)
* data_field
INSERT INTO new_table (date,record_id,data_field)
SELECT date, record_id, data_field开发者_如何学Go FROM old_table
ON DUPLICATE KEY UPDATE date=old_table.data, data_field=old_table.data_field;
I need this to work with a group by and join.. so to edit:
INSERT INTO new_table (date,record_id,data_field,value)
SELECT date, record_id, data_field, SUM(other_table.value) as value FROM old_table JOIN other_table USING(record_id) GROUP BY record_id
ON DUPLICATE KEY UPDATE date=old_table.data, data_field=old_table.data_field, value = value;
I can't seem to get the value updated. If I specify old_table.value I get a not defined in field list error.
Per the docs at http://dev.mysql.com/doc/refman/5.0/en/insert-select.html
In the values part of ON DUPLICATE KEY UPDATE, you can refer to columns in other tables, as long as you do not use GROUP BY in the SELECT part. One side effect is that you must qualify nonunique column names in the values part.
So, you cannot use the select query because it has a group by statement. You need to use this trick instead. Basically, this creates a derived table for you to query from. It may not be incredibly efficient, but it works.
INSERT INTO new_table (date,record_id,data_field,value)
SELECT date, record_id, data_field, value
FROM (
SELECT date, record_id, data_field, SUM(other_table.value) as value
FROM old_table
JOIN other_table
USING(record_id)
GROUP BY record_id
) real_query
ON DUPLICATE KEY
UPDATE date=real_query.date, data_field=real_query.data_field, value = real_query.value;
While searching around some more, I found a related question: "MySQL ON DUPLICATE KEY UPDATE with nullable column in unique key".
The answer is that VALUES()
can be used to refer to column "value" in the select sub-query.
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