數(shù)據(jù)庫錯(cuò)誤: [You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'limit 1' at line 1]
select title from `demo_menu` where id= limit 1
數(shù)據(jù)庫錯(cuò)誤: [Table 'my8907748842.demo_' doesn't exist]
SELECT title,keywords,description FROM `demo_` where id=949
小編直接告訴大家,這個(gè)是必然,就和魚缸水泵一樣,吸程越長越費(fèi)勁,流量也會(huì)隨之衰減。
蠕動(dòng)泵在具備傳輸液體的能力的同時(shí)還具備自吸的能力,理論上在同一個(gè)大氣壓力下,傳輸吸程可達(dá)10M左右,但在實(shí)際情況下蠕動(dòng)泵流量會(huì)有所衰減,而且吸程每增加一米,蠕動(dòng)泵的流量會(huì)衰減約15%,如果對吸程有很高的需求時(shí),可選擇內(nèi)徑更細(xì),壁厚更厚的軟管,同時(shí)選擇轉(zhuǎn)速更高的驅(qū)動(dòng)器。