Change column data type sql

ALTER TABLE table_name 
ALTER COLUMN column_name new_data_type(size);

ALTER TABLE TableName
MODIFY COLUMN ColumnName DataType;

ALTER TABLE TableName 
ALTER COLUMN ColumnName NVARCHAR(200) [NULL | NOT NULL]

alter table my_table alter column my_column int null

ALTER TABLE schema.table
    ALTER COLUMN column
    DROP DEFAULT;
ALTER TABLE schema.table
    ALTER COLUMN column TYPE INTEGER[]
    USING array[column]::INTEGER[];
ALTER TABLE schema.table
    ALTER COLUMN column SET DEFAULT '{}';