我正在尋找一個位的代碼將: Given regular expression E, derive the longest string X
such that for every S, X is a substring of S iff S will match E
例子: E = "a", X = "a"
E = "^a$", X = "a"
E = "a(b|c)", X = "a"
一個相當複雜的SQL查詢我工作讓我思考(ANSI)SQL的限制: 有沒有一種方法來檢索記錄是最大或最小相對於一任意排序? 換句話說: 鑑於這樣的查詢: SELECT * FROM mytable WHERE <various conditions> ORDER BY <order clause>
是有可能寫的是(通過變換順序條款到別的可能)只返回第一行查詢? 我知道你可以做到這一點使用LIMI