SQL syntax

SQLServerCentral is supported by Red Gate Software Ltd.

Popular Topics

Home

Members

Calendar

Who's On

Home » Article Discussions » Article Discussions by Author » Discuss content posted by mohammadk-1135894 » SQL syntax

38 posts, Page 4 of 4

«««1 2 3 4

SQL syntax

Rate Topic

Display Mode

Topic Options

Author

Message

vk-kirov

Posted Tuesday, June 01, 2010 8:19 AM

Hall of Fame

Group: General Forum Members
Last Login: Yesterday @ 1:32 AM
Points: 3,187, Visits: 4,140

Grant Fritchey (5/28/2010)

I would argue that while all three compile and run, none of them is "correct."

What do you think about the syntax of the following statements?

SELECT column1 * column2 FROM table1
SELECT column1 *column2 FROM table1
SELECT column1* column2 FROM table1
SELECT column1*column2 FROM table1

Probably only the first is correct, while others are "incorrect"? Smile

Post #930713

webrunner

Posted Tuesday, June 01, 2010 8:25 AM

SSCrazy

Group: General Forum Members
Last Login: Wednesday, May 15, 2013 3:05 PM
Points: 2,117, Visits: 2,209

Paul White NZ (5/29/2010)

Nice (but quite shocking!) question. I'm not at all embarrassed to say I got this one wrong.

Yes, Paul, thanks. I too got it wrong and am not ashamed to say so. It didn't occur to me that the first choice could be correct (as in, run without error), even if there would no doubt be a lot of criticism of the formatting from a readability standpoint.

Also, one quibble - well, more of a feature request; I suppose I should submit it to Steve as well: It seems to me that scoring the choice percents individually should be augmented, when checkboxes are presented as question choices, with the percentage of people who got the correct combination of selections correct. For example, in the current question, what percentage of people correctly picked all 3 boxes (versus how many overall picked box 1 vs box 2 vs box 3). That will give you an accurate count of who got the question wholly correct. It may be more trouble to program than it's worth, but it would be cool to see.

- webrunner

-------------------
"The chemistry must be respected." - Walter White

"A SQL query walks into a bar and sees two tables. He walks up to them and says 'Can I join you?'"
Ref.: http://tkyte.blogspot.com/2009/02/sql-joke.html

Post #930722

Hugo Kornelis

Posted Tuesday, June 01, 2010 8:54 AM

SSCertifiable

Group: General Forum Members
Last Login: Today @ 2:01 AM
Points: 5,230, Visits: 7,020

Webrunner, what you ask for is already available:

Above the percentages for the individual options is this:

Correct answers: 62% (1099)
Incorrect answers: 38% (675)
Total attempts: 1774

Hugo Kornelis, SQL Server MVP
Visit my SQL Server blog: http://sqlblog.com/blogs/hugo_kornelis

Post #930750

Steve Jones - SSC Editor

Posted Tuesday, June 01, 2010 8:55 AM

SSC-Dedicated

Group: Administrators
Last Login: Yesterday @ 1:47 PM
Points: 31,406, Visits: 13,722

webrunner, that's a good point. I'll add that to the list, and I like the idea.

Follow me on Twitter: @way0utwest

Forum Etiquette: How to post data/code on a forum to get the best help

Post #930751

UMG Developer

Posted Tuesday, June 01, 2010 8:30 PM

SSCrazy

Group: General Forum Members
Last Login: Monday, May 13, 2013 11:21 AM
Points: 2,163, Visits: 2,148

I think I wouldn't hire anybody that wrote code like that. Using * at all is bad enough. Wink

Post #931065

epriddy

Posted Wednesday, June 02, 2010 12:47 PM

SSC Journeyman

Group: General Forum Members
Last Login: Monday, October 22, 2012 4:46 PM
Points: 77, Visits: 110

lol! Too true! BigGrin

Post #931602

James Goodwin

Posted Thursday, June 03, 2010 8:55 AM

Ten Centuries

Group: General Forum Members
Last Login: Wednesday, April 10, 2013 6:10 AM
Points: 1,322, Visits: 1,070

While I got the answer right, the explanation of the answer: "The "*" Specifies that all columns are returned, so space is not necessary in between, before, or after * in a SELECT statement" doesn't explain what is happening.

The SQL Parser is using non-alphanumeric (or, possibly, reserved) characters to determine the end of each string token. It uses non-numeric characters to determine the end of numeric tokens. Thus SELECT 1FROM <table> works, but SELECT1FROM <table> doesn't.

There was probably no decision made to allow SELECT*FROM. This is probably a result of wanting to allow mathematical formulas without forcing spaces around the operator (e.g.) field1 + 2 vs field1+2.
--
JimFive

Post #932203

L' Eomot Inversé

Posted Wednesday, July 07, 2010 7:05 AM

SSCertifiable

Group: General Forum Members
Last Login: Today @ 7:35 AM
Points: 7,075, Visits: 7,113

Paul White NZ (5/29/2010)

Grant Fritchey (5/28/2010)

I would argue that while all three compile and run, none of them is "correct."

In the same way that 2+2=5 for sufficiently large values of 2? Tongue

I have to agree with Grant. What does the formal syntax definition of a select statement specify? I believe it requires whitespace between the SELECT keyword and the select list. The fact that the T-SQL parser has a wiggle (don't know whether it was an intended feature or an unintended consequence of the handling of * in its multiply operator role, so call it a "wiggle" rather than a "feature or a "bug", although I think "bug" would really be more appropriate) which allows it to correct some incorrect syntax doesn't make that syntax correct, it just makes it usable. Of course I may have misinterpreted the BNF definition of the syntax - maybe someone should check me.

Tom
Que conclure à la fin de tous mes longs propos? C'est que les préjugés sont la raison des sots. (Voltaire, 1756)

Post #948508

« Prev Topic | Next Topic »

38 posts, Page 4 of 4

«««1 2 3 4

Permissions