-- The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. -- The ALTER TABLE statement is also used to add and drop various constraints on an existing table. -- ...

The ALTER TABLE.. ADD COLUMN statement adds a column to an existing table. This operation is online in TiDB, which means that neither reads or writes to the table are blocked by adding a column.

Adds columns to, drops columns from, and changes column attributes in an existing table. Adds, modifies, and drops integrity constraints from an existing table. Restriction: You cannot use any type of ...

i need some help with a SQL alter command. i am trying to add a field to my table, but when i do the field is filled with null in any existing rows. how can i just make it fill blank like the value ...