sql - Is there a difference between NOT (ColumnName LIKE '%a%') and ColumnName NOT LIKE '%a%' -

i came across when amending else's view in sql server.

are there differences between:

not (columnname '%a%') 

and

columnname not '%a%' 

are there performance differences or difference in results? or strange way (strange me anyway) sql server alters code when use query builder or view builder?

no, there's no difference.

the 2 syntaxes both make sense - not like clearer one, it's not can disable not (a simple unary boolean operator) in cases this.

most of time, form of query doesn't matter performance - time does, you're looking @ subtle bug in execution planner. before query gets anywhere close executing, it's torn apart, analyzed , rebuilt actual steps needed results - whenever wonder what's really happening in query, execute include actual execution plan, , you'll see.

if you're human, there's little reason not use not like - you'd use other way part of automatic generation of code (negating result of expression), not in human written code. unless you're building query slapping strings together, of course - might make sense when write yourself.

oh, , style, note said, not operator, not function call. proper way use parentheses either

not columnname '%a%' 

or better,

(not columnname '%a%') 

or, if you're crazy (or again, generating code):

(not (columnname '%a%')) 

using function call syntax might confusing - , operator precedence in t-sql not intuitive (it tries hard easy use , avoid parentheses, kind of confusing sometimes). sql generators tend on cautious side, , use more parentheses strictly necessary, leads better readability (and correctness :)), while having no meaningful performance impact or anything.