Wrong sql query for migration

[mgoldenbe]

I had the model:

`py
class UserInfo(models.Model):

user = models.ForeignKey(User, related_name='user_info', on_delete=CASCADE)
picture = models.URLField(null = True, blank = True)
paying = models.BooleanField(default = False)
credits = models.DecimalField(max_digits=6, decimal_places=2)
expiry = models.DateTimeField()
usd_per_credit = models.FloatField(null = True, blank = True)
content_count = models.IntegerField(default=0)
suspended = models.BooleanField(default = False)
suspended_request = models.TextField(null = True, blank = True)
suspended_timestamp = models.DateTimeField(null = True, blank = True)

def str(self): return str(self.user)

`

Then I changed the usd_per_credit field to be
`

usd_per_credit = models.FloatField(default = 0.00)

`

After running makemigrations and migrate, I ran sqlmigrate and got the following:
`sql
BEGIN;
--
-- Alter field usd_per_credit on userinfo
--
ALTER TABLE "accounts_userinfo" ALTER COLUMN "usd_per_credit" SET DEFAULT 0.0;
UPDATE "accounts_userinfo" SET "usd_per_credit" = 0.0 WHERE "usd_per_credit" IS NULL;
ALTER TABLE "accounts_userinfo" ALTER COLUMN "usd_per_credit" SET NOT NULL;
ALTER TABLE "accounts_userinfo" ALTER COLUMN "usd_per_credit" DROP DEFAULT;
COMMIT;
`

The last line before COMMIT is wrong. It drops the default value which was correctly set.