在 boolean 模式下带有空字符串的 FULLTEXT INDEX 给出错误“语法错误，意外 $end，期望 FTS_TERM 或 FTS_NUMB 或 '*'”

Question

MATCH (a2.name, a2.email) AGAINST ("key*" IN BOOLEAN MODE) //this works
MATCH (a2.name, a2.email) AGAINST ("*" IN BOOLEAN MODE) //doesn’t work 

one option that I have is to write 2 queries on basis of key presence. Is there any other option available?

Answer 1

Your application must observe that the user provided an empty string and do something different than blindly throwing it into AGAINST . In this case, leaving the FT clause out of the WHERE might be 'right', but possible 'slow'.

Also you may want to avoid 1- and 2-character strings. And strings with punctuation. And stop words.

Sometimes it is wise to revert to LIKE '%foo%' when the user provides something that you can predict that FT will "do wrong".