hi! what's the diference between ' != ' and ' NOT ' ?

Answer 1

There is a difference. NOT, as was pointed out, is a logical operator, and as such, you can use it with various conditions. != is a simple comparison with a certain value.
Examples:
SELECT name, age, city, job FROM people WHERE city != 'London';
will give you people from all cities except London.
SELECT name, age, city, job FROM people WHERE age >18 AND NOT (city IN ('Sydney', 'Tokyo') AND job = 'Student')
will give you people who are older than 18, except Students from Sydney or Tokyo.
In a very specific query, the two operators will give the same results (as will <> by the way, which is identical to !=):
SELECT name, city FROM people WHERE city != 'London';
SELECT name, city FROM people WHERE city <> 'London';
SELECT name, city FROM people WHERE NOT (city = 'London');
will all return the same set.

Answer 2

NOT is logical expression which gives complement of any number whereas != means not equals to.

Answer 3

1) NOT is a logical operator. It is applied on conditions. Example : NOT (a>b) is true if the condition 'a>b' is false.
2) != is a comparison operator. It can be used in conditions. Example : (a!=b) is a condition and is true if 'a' is not equal to 'b'.

Simply stating, NOT is applied on conditions whereas != is used to form a condition.

Answer 4

there is no difference . the only thing is that "!=" is used in C++ and "NOT" is used in database...

Answer 5

I've seen the Not operator expressed as <> as well as != , is there a difference in using these operators? ( just piggybacking here)

Answer 6

how to delete duplicate row from table?

Answer 7

thank you guys for all these answers it really helped me know the difference

Answer 8

output of both the statements are same but the syntax may be different.