MySQL: "Select text from... as <variable here or subquery>"

Question

I have the following table which contains the following data:

id	text	language
1	German text	German
2	English text	English

What I want is to get results in the following format:

german="deutscher text"
english="english text"

means not :

text="deutscher text"
text="english text"

Key/column nametext should be data from language

I tried the following query but it doesn't work:

SELECT text as (SELECT language FROM `table` where id = 1) FROM `table` where id = 1;

(SELECT language FROM table where id = 1) will return "german", so the query should be: "Select german text from table where id = 1;" but this doesn't work.

Is there a way to do this in one query?

Cheers, Thomas

Answer 1

You have to change the table schema slightly; added a reference to group by languages ​​you want to use

CREATE TABLE IF NOT EXISTS `test` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `ref` int(11) DEFAULT 0,
  `text` varchar(50) DEFAULT NULL,
  `language` varchar(50) DEFAULT NULL,
  KEY `Index 1` (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb3;

Then SQL

SELECT T.text AS english, T2.text AS german
FROM test T 
INNER JOIN test T2 ON T.ref = T2.ref AND T2.`language` = 'german'
WHERE 
    T.ref = 1 AND
    T.language = 'english'

Virtual data

INSERT INTO `test` (`id`, `ref`, `text`, `language`) VALUES
    (1, 1, 'deutscher text', 'german'),
    (2, 1, 'english text', 'english');

Answer 2

One option you can use is PREPARED STATMENT:

SET @sql := NULL;

SELECT GROUP_CONCAT(
           CONCAT('MAX(CASE WHEN language="',language,'" THEN text END) AS "',language,'"')) 
         INTO @sql
FROM mytable;

SELECT CONCAT('SELECT ',@sql,' FROM mytable;') INTO @sql;

PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;

The first step is to dynamically allocate the columns required by the @sql variable. The previously assigned @sql variable is then concatenated with the rest of the final SELECT query and reassigned to the @sql variable. The query will be as follows:

SELECT MAX(CASE WHEN language="german" THEN text END) AS "german",
       MAX(CASE WHEN language="english" THEN text END) AS "english" 
FROM mytable;

Finally, we prepare, execute and then deallocate the statement allocated in the @sql variable and you will get the expected results.

Demo Violin