Sql server how to change column type from int to date

Question

Sql server how to change column type from int to date

Answer 1

You would need to do one of:

1. Create a new table with the desired schema and copy data over.
2. Add a new column, and copy data over, and then drop the old column.

In either case, you need to know how to convert your current values to date. That is, you need to know which rules to apply.

You cannot use ALTER TABLE, as testified by this example:

CREATE TABLE nisse (a int NOT NULL)
go
ALTER TABLE nisse ALTER COLUMN a date NOT NULL

The error message is:

Msg 206, Level 16, State 2, Line 3 Operand type clash: int is incompatible with date