保留字

SQL 中的一些关键字也是保留字。要在 SQL 语句中使用保留字作为标识符，可用双引号、方括号或反引号将它括起来。SQL 语句中出现的很多关键字都是保留字。例如，使用以下语法可检索名为 SELECT 的表的内容。

SELECT *
   FROM "SELECT"

SQL 关键字不区分大小写，因此以下关键字可能会以大写形式、小写形式或两种形式的任意组合显示。与以下某个字仅在大小写形式上有所不同的所有字符串都是保留字。

也可以使用 non_keywords 选项关闭关键字。

reserved_keywords 选项可打开缺省禁用的各个关键字。

如果使用嵌入式 SQL，可以利用数据库库函数 SQL_needs_quotes 确定一个字符串是否需要加上引号。如果一个字符串是保留字，或者包含标识符中通常不允许的字符，则该字符串需要加上引号。

可以使用 sa_reserved_words 系统过程获得保留字的列表。

SQL Anywhere 中有以下保留的 SQL 关键字：

add	all	alter	and
any	array	as	asc
attach	backup	begin	between
bigint	binary	bit	bottom
break	by	call	capability
cascade	case	cast	char
char_convert	character	check	checkpoint
close	comment	commit	compressed
conflict	connect	constraint	contains
continue	convert	create	cross
cube	current	current_timestamp	current_user
cursor	date	datetimeoffset	dbspace
deallocate	dec	decimal	declare
default	delete	deleting	desc
detach	distinct	do	double
drop	dynamic	else	elseif
encrypted	end	endif	escape
except	exception	exec	execute
existing	exists	externlogin	fetch
first	float	for	force
foreign	forward	from	full
goto	grant	group	having
holdlock	identified	if	in
index	inner	inout	insensitive
insert	inserting	install	instead
int	integer	integrated	intersect
into	is	isolation	join
json	kerberos	key	lateral
left	like	limit	lock
login	long	match	membership
merge	message	mode	modify
natural	nchar	new	no
noholdlock	not	notify	null
numeric	nvarchar	of	off
on	open	openstring	openxml
option	options	or	order
others	out	outer	over
passthrough	precision	prepare	primary
print	privileges	proc	procedure
publication	raiserror	readtext	real
reference	references	refresh	release
remote	remove	rename	reorganize
resource	restore	restrict	return
revoke	right	rollback	rollup
row	rowtype	save	savepoint
scroll	select	sensitive	session
set	setuser	share	smallint
some	spatial	sqlcode	sqlstate
start	stop	subtrans	subtransaction
synchronize	table	temporary	then
time	timestamp	tinyint	to
top	tran	treat	trigger
truncate	tsequal	unbounded	union
unique	uniqueidentifier	unknown	unnest
unsigned	update	updating	user
using	validate	values	varbinary
varbit	varchar	variable	varray
varying	view	wait	waitfor
when	where	while	window
with	within	work	writetext
xml

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