<s>
QUEL	O
is	O
a	O
relational	B-Application
database	I-Application
query	B-Language
language	I-Language
,	O
based	O
on	O
tuple	B-Application
relational	I-Application
calculus	I-Application
,	O
with	O
some	O
similarities	O
to	O
SQL	B-Language
.	O
</s>
<s>
It	O
was	O
created	O
as	O
a	O
part	O
of	O
the	O
Ingres	B-Application
DBMS	B-General_Concept
effort	O
at	O
University	O
of	O
California	O
,	O
Berkeley	O
,	O
based	O
on	O
Codd	O
's	O
earlier	O
suggested	O
but	O
not	O
implemented	O
Data	O
Sub-Language	O
ALPHA	B-Language
.	O
</s>
<s>
QUEL	O
was	O
used	O
for	O
a	O
short	O
time	O
in	O
most	O
products	O
based	O
on	O
the	O
freely	O
available	O
Ingres	B-Application
source	O
code	O
,	O
most	O
notably	O
in	O
an	O
implementation	O
called	O
POSTQUEL	B-Language
supported	O
by	O
POSTGRES	B-Application
.	O
</s>
<s>
As	O
Oracle	B-General_Concept
and	O
DB2	B-Application
gained	O
market	O
share	O
in	O
the	O
early	O
1980s	O
,	O
most	O
companies	O
then	O
supporting	O
QUEL	O
moved	O
to	O
SQL	B-Language
instead	O
.	O
</s>
<s>
QUEL	O
continues	O
to	O
be	O
available	O
as	O
a	O
part	O
of	O
the	O
Ingres	B-Application
DBMS	B-General_Concept
,	O
although	O
no	O
QUEL-specific	O
language	O
enhancements	O
have	O
been	O
added	O
for	O
many	O
years	O
.	O
</s>
<s>
Consider	O
this	O
example	O
,	O
taken	O
from	O
one	O
of	O
the	O
first	O
original	O
Ingres	B-Application
papers	O
:	O
</s>
<s>
An	O
equivalent	O
SQL	B-Language
statement	O
is	O
:	O
</s>
<s>
In	O
this	O
example	O
,	O
the	O
relation	O
is	O
being	O
stored	O
in	O
a	O
new	O
table	O
W	O
.	O
This	O
is	O
not	O
a	O
direct	O
analog	O
of	O
the	O
QUEL	O
version	O
;	O
relations	O
in	O
QUEL	O
are	O
more	O
similar	O
to	O
temporary	O
tables	O
seen	O
in	O
most	O
modern	O
SQL	B-Language
implementations	O
.	O
</s>
<s>
Similar	O
commands	O
are	O
available	O
in	O
many	O
SQL	B-Language
systems	O
,	O
but	O
usually	O
as	O
external	O
tools	O
,	O
as	O
opposed	O
to	O
being	O
internal	O
to	O
the	O
SQL	B-Language
language	I-Language
.	O
</s>
<s>
In	O
contrast	O
,	O
SQL	B-Language
uses	O
only	O
for	O
exact	O
matches	O
,	O
while	O
is	O
used	O
when	O
pattern	O
matching	O
is	O
required	O
.	O
</s>
