Map 结果从一个表到另一个查询中的不同列

Question

I'm trying to retrieve a set of records from table that has descriptions on another table in same database.

1. Table 1:
   ColA1 | DescrpA1
   -- A - - - - Apple
   -- B - - - - Orange
   -- C - - - - Banana
   -- D - - - - Watermelon
   

2. Table 2:
   ColA2 | Qty1 | ColB2 | Qty2 |
   --A - - - - - 1 - - - C - - - - 1
   --C - - - - - 1 - - - D - - - - 2
   --B - - - - - 1 - - - A - - - - 1
   

What I want is a way to map descriptions from Table1 into results of Table2

3. Result:
   ColA2 | Decription | Qty1 | ColB2 | Description | Qty2
   --A - - - - Apple - - - - -1 - - - - C - - - Banana - - - - 1
   --C - - - - Banana - - - 1 - - - - D - - - Watermelon - 2
   --B - - - - Orange - - - 1 - - - - A - - - Apple - - - - - - 1
   

Sorry about the formatting. first time posting a questi

Answer 1

You want to join the tables. . . twice:

select t2.cola2, t1_a.DescrpA1, t2.colb2, t1_b.DescrpA1
from table2 t2 join
     table1 t1_a
     on t2.cola2 = t1_a.cola1 join
     table1 t1_b
     on t2.colb2 = t1_b.cola1;