问题
I have a table CANDIDATE in my db which is running under MySQL 5.5 and I am trying to get rows from table where RAM is contains in firstname, so I can run below two queries, but I would like to now which query we should use for long term with respect to optimization.
SELECT * FROM CANDIDATE c WHERE firstname REGEXP 'ram';
SELECT * FROM CANDIDATE c WHERE firstname LIKE'%ram%';
回答1:
REGEXP and LIKE are used to totally different cases.
LIKE is used to add wildcards to a string whereas REGEXP is used to match an attribute with Regular Expressions.
In your case a firstname is more likely to be matched using LIKE than REGEXP and hence, it will be more optimized.
回答2:
If you can use LIKE instead of REGEXP, use LIKE
回答3:
Better Use of LIKE Query instead of REGEXP if you are not sure about value.
Also LIKE is much faster than REGEXP.
回答4:
I've tried it out on MySQL 8.0.13 and compared LIKE vs REGEXP on a table with 1M+ rows on a column with an index:
SELECT * FROM table WHERE column LIKE '%foobar%';
Query took 10.0418 seconds.
SELECT * FROM table WHERE REGEXP_LIKE(column, 'foobar');
Query took 11.0742 seconds.
LIKE performance is faster. If you can get away with using it instead of REGEXP, do it.
来源：https://stackoverflow.com/questions/16646686/mysql-regexp-vs-like