Question

我正在查询带有文字字段的表格

| ID | Field1  | Field2  | Field3  |
| 1  | a       | random  | random  |
| 2  | a       | b       | random  | <- second best match
| 3  | random  | b       | random  |
| 4  | a       | b       | c       | <- best match

SELECT * 
FROM table 
WHERE (Field1 = 'a' OR Field2 = "b" OR Field3 = "c")

所有行都遵循WHERE中的条件，但我需要对结果进行排序，以便考虑匹配字段的数量以便返回

4, 2, 1, 3

Answer 1

http://sqlfiddle.com/#!9/b9361/7

SELECT t.*, 
  IF(Field1 = 'a',1,0) aFlag, 
  IF(Field2 = "b",1,0) bFlag, 
  IF(Field3 = "c",1,0) cFlag
FROM table1 t
WHERE (Field1 = 'a' OR Field2 = "b" OR Field3 = "c")
ORDER BY (aFlag+bFlag+cFlag) DESC

更新根据可能有用的@Neal评论：

SELECT t.*
FROM table1 t
WHERE (Field1 = 'a' OR Field2 = "b" OR Field3 = "c")
ORDER BY (IF(Field1 = 'a',1,0) +
  IF(Field2 = "b",1,0) + 
  IF(Field3 = "c",1,0) ) DESC

Answer 2

select id, (if(Field1 = 'a', 1, 0) + if(Field2 = "b", 1, 0) + if(Field3 = "c", 1, 0)) c 
    from table 
    order by c desc

Answer 3

当MySQL将布尔表达式计算为1或0时，聪明的solution by Alex可以进一步简化为：

SELECT * FROM table1 
WHERE (Field1 = 'a' OR Field2 = 'b' OR Field3 = 'c')
ORDER BY ((Field1 = 'a') + (Field2 = 'b') + (Field3 = 'c')) DESC

请注意，这取决于表达式中的字段不为空。如果它可以为null，则需要使用IF(Field1 = 'a',1,0)或(coalesce(Field1,0) = 'a')才能获得正确的结果。

按大多数匹配字段排序

3 个答案: