How to create column and copy another column into the newly created one

I'm trying to achieve a simple task, I create a new column in a table and immediately afterwards try to copy a value of some other column in the same table into the new created column but I got a

Invalid column name 'COMMENT_TMP'. error

The SQL is

Invalid column name 'COMMENT_TMP'.

ALTER TABLE TASK_COMMENT ADD COMMENT_TMP text;
开发者_运维问答UPDATE TASK_COMMENT SET TASK_COMMENT.COMMENT_TMP = COMMENT;

Add the batch delimiter and the table name in your update statement.

ALTER TABLE TASK_COMMENT ADD COMMENT_TMP text;

GO

UPDATE TASK_COMMENT SET COMMENT_TMP = COMMENT;

You first need to send theALTER batch to the server before executing the UPDATE. Add GO after the ALTER statement