search(string[, pos[, endpos]]) Scan through string looking for a location where this regular expression produces a match, and return a corresponding MatchObject instance. Return None if no position in the string matches the pattern; note that this is different from finding a zero-length match at...
执行 explain SELECT * FROM teacher WHERE tname = "张三" extra为空执行 explain SELECT * FROM teacher WHERE tname = "张三" order by tcidextra 为 Using index condition; Using filesort我的疑问是:为什么第一条执行的时候不是Using index condition?