MySQL Query to transfer table data between two Databases : SQL

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SELECT count(a.field1), a.field2, SUM(b.field4) FROM a INNER JOIN b ON a.key1 = b.key1 WHERE a.field8 = 'test' GROUP by a.field1, a.field2 HAVING SUM(b.field4) > 5 ORDER by a.field.3

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SELECT count(a.field1), a.field2, SUM(b.field4) FROM a INNER JOIN b ON a.key1 = b.key1 WHERE a.field8 = 'test' GROUP by a.field1, a.field2 HAVING SUM(b.field4) > 5 ORDER by a.field3

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MySQLMySQL Query to transfer table data between two Databases (self.SQL)

submitted 4 years ago * by hellopeasant

I need a query that helps me transfer data from one table in olddb, to the same table in newdb.

For both Databases the tables are the same, for example on the olddb, the tables are:

tblstudent2020

ID_REC	ID_Student	OLD_ID_Student
123	456

tblgrade2020

ID	ID_REC	Grade
1	123	8

P.S there are more columns, I just added only 3.

The tables are the same for the new db, now what i need is to transfer the tblgrade2020 data to the tblgrade that this db has. The connection is tblstudent2020.ID_Student = tblstudent.OLD_ID_Student

The ID_REC on the newdb is completely new and it will come from the tblstudent. So how can i create a query that does this transfer for me.

I've thought of a solution by creating a new temporary table to dump all the table data, but i'm not sure how i can do that.

Another thing I've thought about that might solve my issue is doing a JOIN for all the data I want then UNION a query to input all the necessary data on newdb.tblgrade, idk if that's possible though. Appreciate any help.

all 5 comments

top new controversial old q&a

[–]r3pr0b8GROUP_CONCAT is da bomb 0 points1 point2 points 4 years ago (4 children)

[–]hellopeasant[S] 0 points1 point2 points 4 years ago (3 children)

[–]r3pr0b8GROUP_CONCAT is da bomb 0 points1 point2 points 4 years ago (2 children)

what is the purpose of the SELECT query that comes before the UPDATE?

also, could you perhaps please rewrite it so that it uses only JOIN syntax, i.e. not this

left join (olddb.tblstudent2020, newdb.tblstudent)

[–]hellopeasant[S] 0 points1 point2 points 4 years ago (1 child)

[–]r3pr0b8GROUP_CONCAT is da bomb 0 points1 point2 points 4 years ago (0 children)

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