在MySQL中,有特定語義的單詞或者字符串比如delete,order等語法用詞,count,sum等函數用詞,我們把它稱作MySQL保留字;
我們在數據庫設計時,也就是在創建庫表的時候,要避免使用這些字符串作為庫表的某些字段名稱,如果使用了,那么在sql語句中,要使用[]或者``以示區別,不然語句無法執行。
還記得那個update語句吧:
update dmz.award_inform set `Get`=1 where RoleID=290707225 and ZoneID=5;
在沒加反引號之前,怎么執行都報錯,而且是語法錯,但語法能有啥啥錯呢?
后來實在沒辦法聯系了DBA的同學,他說給Get加個反引號試試。。。
之后我意識到sql規范的重要性,就挺突然的!
這里給大伙大致羅列下MySQL中的保留字:(阿里整理的)
action add aggregate all
alter after and as
asc avg avg_row_length auto_increment
between bigint bit binary
blob bool both by
cascade case char character
change check checksum column
columns comment constraint create
cross current_date current_time current_timestamp
data database databases date
datetime day day_hour day_minute
day_second dayofmonth dayofweek dayofyear
dec decimal default delayed
delay_key_write delete desc describe
distinct distinctrow double drop
end else escape escaped
enclosed enum explain exists
fields file first float
float4 float8 flush foreign
from for full function
global grant grants group
having heap high_priority hour
hour_minute hour_second hosts identified
ignore in index infile
inner insert insert_id int
integer interval int1 int2
int3 int4 int8 into
if is isam join
key keys kill last_insert_id
leading left length like
lines limit load local
lock logs long longblob
longtext low_priority max max_rows
match mediumblob mediumtext mediumint
middleint min_rows minute minute_second
modify month monthname myisam
natural numeric no not
null on optimize option
optionally or order outer
outfile pack_keys partial password
precision primary procedure process
processlist privileges read real
references reload regexp rename
replace restrict returns revoke
rlike row rows second
select set show shutdown
smallint soname sql_big_tables sql_big_selects
sql_low_priority_updates sql_log_off sql_log_update sql_select_limit
sql_small_result sql_big_result sql_warnings straight_join
starting status string table
tables temporary terminated text
then time timestamp tinyblob
tinytext tinyint trailing to
type use using unique
unlock unsigned update usage
values varchar variables varying
varbinary with write when
where year year_month zerofill
其實不論是否使用到了保留字,我們都需要規范我們的sql語句!~
以上。