在Spring和HQL中实现搜索功能

Question

I am implementing search in my spring boot app. Search term is searching through first name, last name and email. In my database I store name in two columns: first name and last name. What I want to achieve is to let the user type in the full name (first name + last name) and search the database. I tried this, but when all parameters are empty this query returns me empty set, and I expected it to return all users.

   @Query("FROM Employee e WHERE "
            + "lower(concat(e.firstName,' ',e.lastName)) like lower('%'+':fullName'+'%') AND "
            + "lower(e.email) like lower('%'+':email'+'%')")
    public Page<Employee> search(@Param(value = "fullName") String fullName,
                                 @Param(value = "email") String email,
                                                         Pageable page);

I am not sure if I can use concat like this. If that is a problem is there an alternative?

Edit

I've tried removing % signs from query and it worked. It seems I just have to place them right, but I don't know how.

This worked:

@Query("FROM Employee e WHERE "
            + "lower(concat(e.firstName,' ',e.lastName)) like lower(:fullName) AND "
            + "lower(e.email) like lower(:email)")
    public Page<Employee> search(@Param(value = "fullName") String fullName,
                                 @Param(value = "email") String email,
                                                         Pageable page);

The question is only how to use % .

Answer 1

The problem is probably that HQL interprets this part of the query in a way that does not suit your need :

lower(e.email) like lower('%'+':email'+'%')")

From the HQL specification , I know that the "+" sign is allowed as an arithmetic operator, but I'm not sure it is allowed in any other use.

Obviously, your statement "means something", as Hibernate does not report it as a syntax error, but I'm at a loss to know what it does mean, seeing we are not in an arithmetic context. Maybe it concatenates the string but does not replace the placeholder ? It would be interesting to have Hibernate activate the showSQL and log it, or to see the compiled version of the query object to introspect it, but I have no time to do that right now.

Anyway, in order to achieve the same result, in a predictable way, I suggest you rewrite to

mail like concat('%', lower(:email), '%')

which I find non ambiguous.