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I accidentally removed the WHERE clause from my SQL query in a personal tool. Every row is now the same. I overwrote 206,000+ rows. I have no backup, I am stupid. (lemmy.world)

submitted 1 year ago* (last edited 1 year ago) by [email protected] to c/programming

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"UPDATE table_name SET w = $1, x = $2, z = $4 WHERE y = $3 RETURNING *",

does not do the same as

"UPDATE table_name SET w = $1, x = $2, y = $3, z = $4 RETURNING *",

It's 2 am and my mind blanked out the WHERE, and just wanted the numbers neatly in order of 1234.

idiot.

FML.

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[–] [email protected] 45 points 1 year ago (3 children)

Always SELECT first. No exceptions.

[–] [email protected] 25 points 1 year ago* (last edited 1 year ago)

Better yet... Always use a transaction when trying new SQL/doing manual steps and have backups.

[–] [email protected] 5 points 1 year ago (1 children)

mind explaining?

[–] [email protected] 21 points 1 year ago

By running a select query first, you get a nice list of the rows you are going to change. If the list is the entire set, you'll likely notice.

If it looks good, you run the update query using the same where clause.

But that's for manual changes. OP's update statement looks like it might be generated from code, in which case this wouldn't have helped.

[–] [email protected] 4 points 1 year ago

I did when I made the query a year ago. Dumdum sleep deprived brain thought it would look more organised this way