Question

I have two tables:

table a

ida     valuea
1       a
2       b
3       c
1       d
1       e
2       f

table b

idb      valueb
1 
2

I make valueb as a combobox and need to source it from a query that selects valuea if only ida = current idb.and table b become:

table b

idb      valueb
1        (a,d,e)
2        (b,f)

Answer 1

It is difficult to tell exactly what you are asking, but I think you are either looking for just a simple INNER JOIN:

SELECT  TableB.IDB, TableA.ValueA
FROM    TableB
        INNER JOIN TableA
            ON TableA.IDA = TableB.IDB

Or you need to concatenate the rows from tableA into a single row with IDB. The methods of doing this are DBMS dependant, since you have not specified a DMBS I have answered with as many as I know. Each of which has an example on SQL Fiddle.

---

SQL-Server

SELECT  TableB.IDB,
        STUFF(( SELECT  ', ' + ValueA
                FROM    TableA
                WHERE   TableA.IDA = TableB.IDB
                FOR XML PATH(''), TYPE
                ).value('.', 'VARCHAR(MAX)'), 1, 2, '') AS ValueB
FROM    TableB

---

MySQL/SQLite

SELECT  IDB, 
        GROUP_CONCAT(ValueA) AS ValueB
FROM    TableB
        INNER JOIN TableA
            ON TableA.IDA = TableB.IDB
GROUP BY IDB

---

PostgreSQL

SELECT  IDB,
        ARRAY_AGG(ValueA) AS ValueB
FROM    TableB
        INNER JOIN TableA
            ON TableA.IDA = TableB.IDB
GROUP BY IDB

---

Oracle

SELECT  IDB, 
        LISTAGG(ValueA, ', ') WITHIN GROUP (ORDER BY IDB) AS ValueB
FROM    TableB
        INNER JOIN TableA
            ON TableA.IDA = TableB.IDB
GROUP BY IDB