Update values from one column in same table to another in SQL Server

Question

I'm trying to overwrite values that are found in TYPE1 with values that are found in TYPE2.

I wrote this SQL to try it out, but for some reason it isn't updating:

select * from stuff

update stuff
set TYPE1 = TYPE2
where TYPE1 is null;

update stuff
set TYPE1 = TYPE2
where TYPE1 ='Blank';

http://www.sqlfiddle.com/#!3/a4733/17

Any reason why my values in TYPE1 are not updating?

Answer 1

This works for me

select * from stuff

update stuff
set TYPE1 = TYPE2
where TYPE1 is null;

update stuff
set TYPE1 = TYPE2
where TYPE1 ='Blank';

select * from stuff

Answer 2

UPDATE a
SET a.column1 = b.column2
FROM myTable a 
INNER JOIN myTable b
on a.myID = b.myID

in order for both "a" and "b" to work, both aliases must be defined

Answer 3

UPDATE TABLE_NAME SET COLUMN_A = COLUMN_B;

Much easier. At least on Oracle SQL, i don't know if this works on other dialects as well.

Answer 4

You put select query before update queries, so you just see initial data. Put select * from stuff; to the end of list.

Answer 5

This answer about updating column from a part of another column in the same table.

update T1
set domainname = (New value) --Example: (SELECT LEFT(TableName.col, CHARINDEX('@',TableName.col)-1) STRIPPED_STRING FROM TableName where TableName.col = T2.Emp_ID)
from TableName T1
INNER JOIN
    TableName T2
ON 
    T1.ID= T2.ID;

Answer 6

update TABLE_1 a set COLUMN_1 = (select COLUMN_2 from TABLE_1 b where a.ID = b.ID)

Answer 7

您的选择语句在更新语句之前，请参阅更新的小提琴

Answer 8

UPDATE `tbl_user` SET `name`=concat('tbl_user.first_name','tbl_user.last_name') WHERE student_roll>965

Answer 9

If you need to make an operation on a specific column:

update courses set hours = days * 5