Search engines are integral features to any well designed website, but how well does your search engine work? Most simple search engines work by querying one column of a database for the search terms.

考虑字符串“55,33,255,66,55” 我正在寻找使用mysql select query计算此字符串中特定字符(本例中为“55”)的出现次数的方法. 目前我使用以下逻辑来计算 select CAST((LENGTH("55,33,255,66,55") - LENGTH(REPLACE("55,33,255,66,55", "55", ""))) / LENGTH("55") AS ...