Which command will using to delete all rows from table truncate or delete ?

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Which command will using to delete all rows from table truncate or delete ?

ahmed_elbarbary.2010

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April 27, 2022 at 5:42 pm

#4023209
I work on sql server 2017
i need to delete all rows from table student_course
but i don't know use
delete from student_course
or
truncate table student_course
table student_course
studentid pk
courseid pk
table student table
studentid pk
table courses
courseid pk
---------------------------------------------
student_course table have relation with courses table and student table
so which command will be used to delete all rows from table student_course
truncate or delete ?
What I have tried:
```
delete from student_course

or

truncate table student_course
```

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homebrew01 SSC Guru Points: 55548 More actions · Answer 1

Both will work, but they are different.

https://www.sqlshack.com/difference-between-sql-truncate-and-sql-delete-statements-in-sql-server/

You've been here 10 years. Easy to search for the answer, if not already known for some reason.

This reply was modified 2 years, 6 months ago by homebrew01.
This reply was modified 2 years, 6 months ago by homebrew01.

Ed B Hall of Fame Points: 3665 More actions · Answer 2

The answer is probably truncate, but both will work.

You can not truncate a table that is referenced by a foreign key constraint, but it seems likely the student_course has relationships that reference the student and course tables, not the other way around. You would not be able to truncate the student or course table, even if the student_course table is empty.

ScottPletcher SSC Guru Points: 101093 More actions · Answer 3

Since TRUNCATE is more efficient, try it first.

If it doesn't work, then use DELETE.

SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".

Jeff Moden SSC Guru Points: 1004318 More actions · Answer 4

There are actually several massive differences between Truncate and Delete. You can read about most of them simply by looking up the commands and reading about them.

One not so well documented difference is that if you have a table that has data in it and it has a Clustered Index on it and you delete all rows, the table will not allow Minimal Logging even when you're setup for it. If you have the same table and you Truncate it, then you can use Minimal Logging with the Clustered Index provided, of course, that the other criteria for Minimal Logging are met.

There's another "Oolie" to be had and I've documented it at the following URL. It has proven extremely valuable to me in the world of ETL where you must first insert data into a table to evaluate it and then update the data with what amount to "Expansive" updates. It isn't documented in any of the MS documentation (in fact, the MS documentation says that it can never happen) that I've ever seen and most people don't even know of it. It will work on a Truncated table with a Clustered Index but will not work after a full table DELETE.

https://www.sqlservercentral.com/articles/some-t-sql-inserts-do-follow-the-fill-factor-sql-oolie

--Jeff Moden

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Johan Bijnens SSC Guru Points: 135369 More actions · Answer 5

Also keep in mind you cannot truncate a table that is parent table for other tables. (FK relationships)

Johan

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Jonathan AC Roberts SSCoach Points: 18352 More actions · Answer 6

Johan Bijnens wrote:

Also keep in mind you cannot truncate a table that is parent table for other tables. (FK relationships)

Though you can disable the foreign keys, then truncate, then enable the foreign keys again.