exactly equal (==)

[Rottdpogs]

Please advice. Does EXACTLY EQUAL (==) on a sql statement differs or the same as equal (=)?

settings:
set exact off
set ansi on

Example:
select * from goods left outer join sales on alltrim(goods.pro_id) = alltrim(sales.pro_id)


I just wanna make sure that my output are correct.

Thanks in advance.

 

[Mike Gagnon]

From the help file:
The == operator can be used when an exact comparison of
character strings is needed. If two character expressions are compared with the == operator, the expressions on both sides of the == operator must contain exactly the same characters, including blanks, to be considered equal. The SET EXACT setting is ignored when character strings are compared using ==. See SET EXACT for more information on using the == operator to compare character strings.

You also can use the equal to (=) operator in this version of Visual FoxPro to determine if two object references refer to the same object.

 

[rgbean]

According to the Help file (you do have one?), SET ANSI ON will cause the EQUAL ('=') compare to act like '=='. A quick test with ANSI ON and OFF should verify this.

Rick

 

[Eguy]

As long as you are using ALLTRIM() on both sides of the = as in your example, you should be OK.

Ed Please let me know if the suggestion(s) I provide are helpful to you.
Sometimes you're the windshield... Sometimes you're the bug.

 

[dgrewe]

I disagree with Eguy
lc1 = "1234"
lc2 = "1234567"
lc1=lc2 is false
lc2=lc1 is true

David W. Grewe
Dave@internationalbid.com

 

[rgbean]

David,
Be cafeful, since SET ANSI is only meaningful inside SQL statements, your comparisons aren't appropriate if just run from the command window (or in a program).

Rick

 

[pxw]

With SQL statements, I agree what dgrewe memtioned above. I am using alltrim()+"==" more than alltrim()+"=" to make sure the output is correct. Can someone tell what is the differenty of running speed between "==" and "="?

Peter