获取匹配的列及其值MySQL

Question

Here is my query:

SELECT ID, Name, Description
FROM MyTable
WHERE NAME LIKE :search OR Description LIKE '%search%' 
      OR Status LIKE '%search%'
      OR ... Many Other Columns LIKE '%search%

When I get the data I display it to the user that they searched for. Now I only display ID, Name & Description . I also want to display which column matched the searching string. If it matched Status I want to display the status of the row, if it matched any other column I want to display the value of that column that it matched.

Does not matter if it matches multiple columns. I only need the first one.

Is this possible without selecting all columns & then running PHP search on each to find out which one matched? Can it be done simply in MySQL?

I want to make it as fast as possible since my search is becoming pretty slow the more columns & more tables I add to the search and do not want this feature to add a lot of overhead.

Answer 1

You can do it a bit messily like this:-

SELECT ID, 
        Name, 
        Description,
        CASE
            WHEN NAME LIKE :search THEN 'NAME'
            WHEN Description LIKE :search THEN 'Description' 
            WHEN Status LIKE :search THEN 'Status' 
            ... Many Other Columns LIKE :search
            ELSE 'Unknown Column'
        END AS MatchingColumn
FROM MyTable
WHERE NAME LIKE :search OR Description LIKE :search OR Status LIKE :search OR 
      ... Many Other Columns LIKE :search

Down side is that you are repeating the (fairly time consuming) checks. Not sure if MySQL manages to optimise these away, but it wouldn't surprise me if not.

Alternative might be do a UNION of queries, one for each condition. Then use this as a sub query to select the max from.

Using UNION would give you something like this. It does have the benefit that each UNIONed query can then use indexes (your current query can't as you are checking different columns ORed together to get a match), assuming the LIKE doesn't use a leading wildcard.

SELECT ID, Name, Description, MAX(MatchingColumn)
FROM
(
    SELECT ID, Name, Description, 'NAME' AS MatchingColumn
    FROM MyTable
    WHERE NAME LIKE :search
    UNION
    SELECT ID, Name, Description, 'Description' AS MatchingColumn
    FROM MyTable
    WHERE Description LIKE :search
    UNION
    SELECT ID, Name, Description, 'Status' AS MatchingColumn
    FROM MyTable
    WHERE Status LIKE :search OR 
) sub0
GROUP BY ID, Name, Description

Answer 2

Consider the following...

DROP TABLE IF EXISTS my_table;

CREATE TABLE my_table
(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, a INT NOT NULL, b INT NOT NULL, c INT NOT NULL);

INSERT INTO my_table (a,b,c) VALUES 
(101,102,103),
(102,103,104),
(103,104,105),
(104,105,106),
(105,106,107);

 SELECT * FROM my_table;
+----+-----+-----+-----+
| id | a   | b   | c   |
+----+-----+-----+-----+
|  1 | 101 | 102 | 103 |
|  2 | 102 | 103 | 104 |
|  3 | 103 | 104 | 105 |
|  4 | 104 | 105 | 106 |
|  5 | 105 | 106 | 107 |
+----+-----+-----+-----+

SELECT id
     , CASE WHEN a LIKE '%04%' THEN 'a' WHEN b LIKE '%04%' THEN 'b' WHEN c LIKE '%04%' THEN 'c' END col 
     , CASE WHEN a LIKE '%04%' THEN a WHEN b LIKE '%04%' THEN b WHEN c LIKE '%04%' THEN c END val 
  FROM my_table;
+----+------+------+
| id | col  | val  |
+----+------+------+
|  1 | NULL | NULL |
|  2 | c    |  104 |
|  3 | b    |  104 |
|  4 | a    |  104 |
|  5 | NULL | NULL |
+----+------+------+