03-filter.md: Drop redundant parentheses

We've had these since 61ae6ff (First three lessons on SQL for beginners, 2013-11-09). Maybe these helped a bit before the keyword capitalization from b248d96 (Merge pull request swcarpentry#38 from timtomch/gh-pages, 2015-02-23), but now I think they just clutter the query. If folks felt that parenthesis were a key to readability, we'd all be writing Lisp, and nobody would bother with operator precedence ;).
uzinaduzina · Mar 26, 2015 · 06563c2 · 06563c2
1 parent dbd1d59
commit 06563c2
Showing 1 changed file with 1 addition and 4 deletions.
diff --git a/03-filter.md b/03-filter.md
@@ -56,17 +56,14 @@ For example,
 we can ask for all information from the DR-1 site collected since 1930:
 
 ~~~ {.sql}
-SELECT * FROM Visited WHERE (site="DR-1") AND (dated<="1930-00-00");
+SELECT * FROM Visited WHERE site="DR-1" AND dated<="1930-00-00";
 ~~~
 
 |ident|site|dated     |
 |-----|----|----------|
 |619  |DR-1|1927-02-08|
 |622  |DR-1|1927-02-10|
 
-(The parentheses around the individual tests aren't strictly required,
-but they help make the query easier to read.)
-
 > Most database managers have a special data type for dates.
 > In fact, many have two:
 > one for dates,