Topic solicitation: excuse me each project to save process with an empty string, usually is null, or a ' '?
A: null B: 'C: D: according to circumstances to see the big ye

CodePudding user response:

C: according to the case may be

CodePudding user response:

I usually deposit when use null
When the query with a isnull (col, ' ') & lt;> '

CodePudding user response:

sunny flowers quote 2 floor response:

general deposit when I use the null
When the query with a isnull (col, ' ') & lt;> '

you this operation will lead to failure altogether

CodePudding user response:

B
Fields are the default empty strings, does not allow null
Such judgment, simple, and use the index