我有一个包含许多列的用户表，它看起来大致像这样：

dname:             { type: string(255), notnull: true }
email:             { type: string(255), notnull: true, unique: true }
email_code:        { type: string(255) }
email_confirmed:   { type: boolean, default: false }
profile_filled:    { type: boolean, default: false }
password:          { type: string(255), notnull: true }
image_id:          { type: integer }
gender:            { type: enum, values: [male, female] }
description:       { type: string }
dob:               { type: date }
height:            { type: integer(3) }
looks:             { type: enum, values: [thin, average, athletic, heavy] }
looking_for:       { type: enum, values: [marriage, dating, friends] }
looking_for_age1:  { type: integer }
looking_for_age2:  { type: integer }
color_hair:        { type: enum, values: [black, brown, blond, red] }
color_eyes:        { type: enum, values: [black, brown, blue, green, grey] }
marital_status:    { type: enum, values: [single, married, divorced, widowed] }
smokes:            { type: enum, values: [no, yes, sometimes] }
drinks:            { type: enum, values: [no, yes, sometimes] }
has_children:      { type: enum, values: [no, yes] }
wants_children:    { type: enum, values: [no, yes] }
education:         { type: enum, values: [school, college, university, masters, phd] }
occupation:        { type: enum, values: [no, yes] }
country_id:        { type: integer }
city_id:           { type: integer }
lastlogin_at:      { type: timestamp }
deleted_at:        { type: timestamp }

我创建了一个包含大多数字段（枚举，国家/地区，城市）的表单，该表单使用户能够根据他们选择的字段生成一个where语句。因此，如果有人选择抽烟：否和country_id：7，则sql
where语句可能如下所示：

SELECT id 
FROM user u 
WHERE u.deleted_t IS NULL AND u.profile_filled IS NOT NULL AND smokes = 'no' AND country_id = 7;

由于用户可以选择要过滤的字段的任意组合，因此我不确定如何索引该表，我是否应该在所有可以过滤的字段上创建一个单列索引？您有什么建议？