您可以像这样连接first_name和last_name列，并使用该值进行搜索：

customers = customers.where("identifier 
LIKE ? OR (first_name || ' ' || last_name) 
LIKE ? OR customers.email LIKE ? OR institutional_groups.name 
LIKE ?", q, "%#{q}%", q, q) 
if q.present?

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让我们考虑这四种情况：

*只有名字搜索first_name LIKE :query
*只有姓氏搜索last_name LIKE :query
*名后接姓搜索CONCAT(first_name, ' ', last_name) LIKE :query
*姓氏后接名字搜索CONCAT(last_name, ' ', first_name) LIKE :query

对于部分匹配，可以用%包围query。

Customer.where("
   first_name LIKE :query OR 
   last_name LIKE :query OR 
   CONCAT(first_name, ' ', last_name) LIKE :query OR
   CONCAT(last_name, ' ', first_name) LIKE :query
", query: "%#{query}%")

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对于完全匹配，请删除%字符。

Customer.where("
  first_name LIKE :query OR 
  last_name LIKE :query OR 
  CONCAT(first_name, ' ', last_name) LIKE :query OR
  CONCAT(last_name, ' ', first_name) LIKE :query
", query: query)

型
参考文献：

• CONCAT功能（https://www.postgresqltutorial.com/postgresql-string-functions/postgresql-concat-function/）