Re: [SQL] a wierd query

[Silke Trißl]

[EMAIL PROTECTED] schrieb:

hi 

i have a wierd problem and i require an equally weird query.
1) backgound
 Table test:
   CREATE TABLE main_table (
              string_A varchar( 20),
              string_B varchar( 20),
              );
    -- both columns are identical in nature and usage
    INSERT INTO main_table VALUES('abcd','qrst');
    INSERT INTO main_table VALUES('efgh','efgh');
    INSERT INTO main_table VALUES('ijkl','abcd');
    INSERT INTO main_table VALUES('abcd','ijkl');
    INSERT INTO main_table VALUES('qrst','uvwx');
2) problem:
  
    i require a query that gives me a result set of the form

  'abcd'
  'efgh'
  'ijkl'
  'qrst'
  'uvwx'
  that is i require the dictinct values from (visualizing each column
result as a set) the union of the two columns
3) questions

  a) is a query like this possible that can give me the desired result
  b) if so what would it be.
Yes, the follwoing
select t1.string_a from main_table t1
union
select t2.string_b from main_table t2;
4) remarks
  
   i can get the solution using a temporary table and with repeated
     "insert into temporary select $column from main_table"
 

Why, SQL does the trick!


thanks in advance

ashok

 

Silke

 



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