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Using == vs =
Message
De
08/11/2015 13:59:12
John Ryan
Captain-Cooker Appreciation Society
Taumata Whakatangi ..., Nouvelle Zélande
 
 
À
08/11/2015 13:55:46
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Titre:
Versions des environnements
Visual FoxPro:
VFP 9 SP2
OS:
Windows 10
Network:
Windows 2008 Server
Database:
MS SQL Server
Application:
Web
Divers
Thread ID:
01627149
Message ID:
01627225
Vues:
83
>>I am absolutely convinced that you are wrong. I am curious to see if you can prove your statement.

I think we're both right- sort of! VFP Help confirms that if two strings are compared with the == operator, the expressions must contain exactly the same characters, including blanks, to be considered equal and that SET EQUAL is ignored.
CREATE CURSOR c1 (myfield1 c(10),myfield2 c(11))

? c1.myfield1==c1.myfield2
? c1.myfield2==c1.myfield1

INSERT INTO c1 VALUES ("Hello","Hello")

? c1.myfield1==c1.myfield2
? c1.myfield2==c1.myfield1
.F.
.F.
.F.
.F.

This is what I focused on as Walter said this wasn't about VFP data. However if using SQL, including in a resultset from a backend: == acts the same as = with SET ANSI ON- IOW the shorter string is padded.
CREATE CURSOR c1 (myfield1 c(10), myfield2 c(11))
INSERT INTO c1 VALUES ("Hello","Hello")
SELECT * FROM c1 WHERE myfield1==myfield2
? _TALLY
1
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us.
"
-- Shakespeare: Coriolanus, Act 1, scene 1
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