我这里整理了PHP和MySQL的保留字和关键，供大家参考。
PHP关键词
这些词语在 PHP 中有着特殊的意义。它们中有些像是函数，有些像是常量……但是它们不是的，它们只是语言结构的一部分。不能使用它们的任何一个作为常量、方法名或是类名。但是可以将它们作为变量名使用，不过这样会导致混淆。
and
or
xor
__FILE__
exception (PHP 5)
__LINE__
array()
as
break
case
class
const
continue
declare
default
die()
do
echo
else
elseif
empty()
enddeclare
endfor
endforeach
endif
endswitch
endwhile
eval()
exit()
extends
for
foreach
function
global
if
include
include_once
isset()
list()
new
print
require
require_once
return
static
switch
unset()
use
var
while
__FUNCTION__
__CLASS__
__METHOD__
final (PHP 5)
php_user_filter (PHP 5)
interface (PHP 5)
implements (PHP 5)
extends
public (PHP 5)
private (PHP 5)
protected (PHP 5)
abstract (PHP 5)
clone (PHP 5)
try (PHP 5)
catch (PHP 5)
throw (PHP 5)
cfunction (PHP 4 only)
this (PHP 5 only) MySQL保留字在MySQL中，下表中的字显式被保留。其中大多数字进制被标准SQL用作列名和/或表名(例如，GROUP)。少数被保留了，因为MySQL需要它们，(目前)使用yacc解析程序。保留字被引起来后可以用作识别符。
ADD
ALL
ALTER
ANALYZE
AND
AS
ASC
ASENSITIVE
BEFORE
BETWEEN
BIGINT
BINARY
BLOB
BOTH
BY
CALL
CASCADE
CASE
CHANGE
CHAR
CHARACTER
CHECK
COLLATE
COLUMN
CONDITION
CONNECTION
CONSTRAINT
CONTINUE
CONVERT
CREATE
CROSS
CURRENT_DATE
CURRENT_TIME
CURRENT_TIMESTAMP
CURRENT_USER
CURSOR
DATABASE
DATABASES
DAY_HOUR
DAY_MICROSECOND
DAY_MINUTE
DAY_SECOND
DEC
DECIMAL
DECLARE
DEFAULT
DELAYED
DELETE
DESC
DESCRIBE
DETERMINISTIC
DISTINCT
DISTINCTROW
DIV
DOUBLE
DROP
DUAL
EACH
ELSE ELSEIF
ENCLOSED
ESCAPED
EXISTS
EXIT
EXPLAIN
FALSE
FETCH
FLOAT
FLOAT4
FLOAT8
FOR
FORCE
FOREIGN
FROM
FULLTEXT
GOTO
GRANT
GROUP
HAVING
HIGH_PRIORITY
HOUR_MICROSECOND
HOUR_MINUTE
HOUR_SECOND
IF
IGNORE
IN
INDEX
INFILE
INNER
INOUT
INSENSITIVE
INSERT
INT
INT1
INT2
INT3
INT4
INT8
INTEGER
INTERVAL
INTO
IS
ITERATE
JOIN KEY
KEYS KILL
LABEL
LEADING
LEAVE
LEFT
LIKE
LIMIT
LINEAR
LINES
LOAD
LOCALTIME
LOCALTIMESTAMP
LOCK
LONG
LONGBLOB
LONGTEXT
LOOP
LOW_PRIORITY
MATCH
MEDIUMBLOB
MEDIUMINT
MEDIUMTEXT
MIDDLEINT
MINUTE_MICROSECOND
MINUTE_SECOND
MOD
MODIFIES NATURAL
NOT
NO_WRITE_TO_BINLOG
NULL
NUMERIC
ON
OPTIMIZE OPTION
OPTIONALLY
OR
ORDER
OUT
OUTER
OUTFILE
PRECISION
PRIMARY
PROCEDURE
PURGE
RAID0
RANGE
READ
READS
REAL
REFERENCES
REGEXP
RELEASE
RENAME
REPEAT
REPLACE
REQUIRE
RESTRICT
RETURN
REVOKE
RIGHT
RLIKE
SCHEMA
SCHEMAS
SECOND_MICROSECOND
SELECT
SENSITIVE SEPARATOR
SET
SHOW
SMALLINT
SPATIAL
SPECIFIC SQL
SQLEXCEPTION
SQLSTATE
SQLWARNING
SQL_BIG_RESULT
SQL_CALC_FOUND_ROWS
SQL_SMALL_RESULT
SSL
STARTING
STRAIGHT_JOIN
TABLE
TERMINATED
THEN
TINYBLOB
TINYINT
TINYTEXT
TO
TRAILING
TRIGGER
TRUE
UNDO
UNION
UNIQUE
UNLOCK
UNSIGNED
UPDATE
USAGE
USE
USING
UTC_DATE
UTC_TIME
UTC_TIMESTAMP
VALUES
VARBINARY
VARCHAR
VARCHARACTER
VARYING
WHEN
WHERE
WHILE
WITH
WRITE
X509
XOR
YEAR_MONTH
ZEROFILL以上内容引用自PHP手册及MySQL手册 最佳答案
