Company mysql specification must not null but goods in different shops are from station synchronization in the past of some commodity no inventory field is set to set the default value of 0 or null good but does not allow null again

CodePudding user response:

Business field generally cannot be null, if not, you give an initial value (or the default value), digital class to 0, the string class to an empty string,
You use null, although put into simple, but the query is very troublesome, if you are looking for some products, you should also consider the number is 0 and the fields are null two situations, you have,