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simple explanation please

P: n/a
Jay
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay
Jul 23 '05 #1
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5 Replies


P: n/a
Hi

You need to check the index!
Predicate
Is an expression that evaluates to TRUE, FALSE, or UNKNOWN. Predicates are
used in the search condition of WHERE clauses and HAVING clauses, and the
join conditions of FROM clauses.

John

"Jay" <nospam@*here.com> wrote in message
news:6b*******************@news.xtra.co.nz...
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay

Jul 23 '05 #2

P: n/a
Jay
Thanks... I should have said that I found it in BOL but came away none the
wiser.
OK so it's T/F or Unknown.... but what is it?

Jay

"John Bell" <jb************@hotmail.com> wrote in message
news:41**********************@news.easynet.co.uk.. .
Hi

You need to check the index!
Predicate
Is an expression that evaluates to TRUE, FALSE, or UNKNOWN. Predicates are
used in the search condition of WHERE clauses and HAVING clauses, and the
join conditions of FROM clauses.

John

"Jay" <nospam@*here.com> wrote in message
news:6b*******************@news.xtra.co.nz...
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay


Jul 23 '05 #3

P: n/a
On Sun, 12 Dec 2004 14:30:39 +1300, Jay wrote:
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay


Hi Jay,

You can't use the literal "PREDICATES" in a WHERE clause (or aywhere elses
in a query). Instead, predicate is the name given to all expression that
evaluate to true, false or unknown (as opposed to non-predicate
expressions that evaluate to an integer value, a string, a datetime value,
etc.)

Examples of predicates are
fname LIKE 'Ja%'
ytd_sales > 4095 AND ytd_sales < 12000
AVG(price) > 10.95
EXISTS (insert subquery here)
Best, Hugo
--

(Remove _NO_ and _SPAM_ to get my e-mail address)
Jul 23 '05 #4

P: n/a
Hi Jay

It is an expression which is also in the BOL index, but the topic "Search
Conditions" is probably the best example for predicates

< predicate > ::=
{ expression { = | < > | ! = | > | > = | ! > | < | < = | ! < }
expression
| string_expression [ NOT ] LIKE string_expression
[ ESCAPE 'escape_character' ]
| expression [ NOT ] BETWEEN expression AND expression
| expression IS [ NOT ] NULL
| CONTAINS
( { column | * } , '< contains_search_condition >' )
| FREETEXT ( { column | * } , 'freetext_string' )
| expression [ NOT ] IN ( subquery | expression [ ,...n ] )
| expression { = | < > | ! = | > | > = | ! > | < | < = | ! < }
{ ALL | SOME | ANY} ( subquery )
| EXISTS ( subquery )

John
"Jay" <nospam@*here.com> wrote in message
news:zf*******************@news.xtra.co.nz...
Thanks... I should have said that I found it in BOL but came away none the
wiser.
OK so it's T/F or Unknown.... but what is it?

Jay

"John Bell" <jb************@hotmail.com> wrote in message
news:41**********************@news.easynet.co.uk.. .
Hi

You need to check the index!
Predicate
Is an expression that evaluates to TRUE, FALSE, or UNKNOWN. Predicates
are used in the search condition of WHERE clauses and HAVING clauses, and
the join conditions of FROM clauses.

John

"Jay" <nospam@*here.com> wrote in message
news:6b*******************@news.xtra.co.nz...
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay



Jul 23 '05 #5

P: n/a
Jay

"Hugo Kornelis" <hugo@pe_NO_rFact.in_SPAM_fo> wrote in message
news:qj********************************@4ax.com...
On Sun, 12 Dec 2004 14:30:39 +1300, Jay wrote:
PREDICATES

Used as a clause.
A. What does PREDICATES mean?
B. What does it mean when used in a where clause?

I checked BOL (Glossary) but get no explanation there.

Thanks
Jay


Hi Jay,

You can't use the literal "PREDICATES" in a WHERE clause (or aywhere elses
in a query). Instead, predicate is the name given to all expression that
evaluate to true, false or unknown (as opposed to non-predicate
expressions that evaluate to an integer value, a string, a datetime value,
etc.)

Examples of predicates are
fname LIKE 'Ja%'
ytd_sales > 4095 AND ytd_sales < 12000
AVG(price) > 10.95
EXISTS (insert subquery here)
Best, Hugo

Ahh many thanks Hugo,
Now I see the light.

Jay
Jul 23 '05 #6

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