关于列中的选择查询-MySQL

Question

Want to have the multiple columns returned from select query in the column of the main select query. Getting mysql error. How can I do it?

SELECT test.val1, 
   (SELECT 
     cc.id, cc.nbr,cc.addr
     FROM
        (
          Select temptable.id ,temptable.nbr,temptable.addr
          from temptable
          inner join temptable2  on temptable2.id=temptable.id
        )  cc),
       test.val2,
       test.val3
 FROM test 
 innerjoin test2 on test.id=test2.id

Answer 1

A subquery in the select list has to return 1 field and 1 record. If you want values from multiple fields to appear in a single column, then you can use concat() or concat_ws() mysql functions to concatenate them into a single field. If you want to combine multiple fields and multiple rows into one field, then above the afore mentioned 2 functions you will need group_concat() .

select concat_ws(';',field1, field2) from table

However, I think in this particular case you may want to place the subquery into the from clause and reference the columns from there in the select clause.

Answer 2

Please try the below if the four tables are related.

select tb1.tb_id, tb1.val1, tb2.tb_id from (select test.id as tb_id, val1, val2, val3 from test inner join test2 on test.id=test2.id) as tb1 join (select temptable.id as tb_id from temptable join temptable2 on temptable.id=temptable2.id) as tb2 on tb2.tb_id=tb1.tb_id;