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It's not really important, but just wondering why the Oracle SQL seems to be quote inconsistent? I mean why do they have...

NOT IN (?,?,?)

and

!= '?'

rather than 

NOT EQ '?'

Just a thought

K

KS1
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  • With `NOT IN (?,?,?)` you compare to a **list of expressions** (or subquery), e.g. numbers. With `!= '?'` you compare with a single **string** literal. Oracle is consistent in this. – Wernfried Domscheit May 02 '18 at 10:40
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    i think you're confusing some things. NOT IN is used to compare with a list of values. The != operator is to compare one value with another. A similar notion to what you wrote as NOT EQ '?' might be the NOT LIKE '?' – Renato Afonso May 02 '18 at 10:45
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    Actually it's `<> '?'` in standard SQL –  May 02 '18 at 10:45

2 Answers2

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NOT IN ( ?, ? ) is ISO 9075 SQL standard syntax. I do wonder what symbols could possibly be used to denote "not in". That seems silly, since "mathematical" symbols such as != are almost self-documenting, and the "set" type symbols needed for "not in" aren't available on most keyboards, nor would they be familiar to most developers.

Note that neither != nor NOT EQ are ISO-standard. The standard "not equals operator" is <>, but as noted here, the != has some advantages.

Andrew Henle
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In the code NOT IN (?,?,?) the question marks appear to be positional parameters from a parameterized query, while the code != '?' is a comparison to a string literal. If you had wanted it parameterized it would have been != ? without the single quotes.

Sentinel
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