通过匹配列的值从两个数据库中提取数据

Question

"I am writing a query to match data from one database table to another database table"

          Database 1.Table1:      number  CFG    Name
                                   A123   28A    tom
                                   B123   23C    sindy

          Database2.Table2:       ITEM   results
                                   28A    yes
                                    23C   no

If I search for Number like A123, it must match these columns CFG and ITEM and it brings up like CFG, ITEM, Results."

SELECT database1.table1.number, database1.table1.CFG, database2.table2.ITEM,database2.table2.results 

FROM database1.table1, database2.table2
Where database1.table1.number ='A123'
AND database1.table1.CFG = database2.table2.ITEM 

"I expect the output of like CFG ITEM results, it's displaying nothing"

Answer 1

I prepared your statement for testing, if this works for you replace declared tables with databaseN.tableN.

DECLARE @Database1Table1 TABLE
                     (number VARCHAR(10) NOT NULL PRIMARY KEY,
                      CFG VARCHAR(10) NOT NULL,
                      Name NVARCHAR(50) NULL)

DECLARE @Database2Table2 TABLE
                     (ITEM VARCHAR(10) NOT NULL PRIMARY KEY,
                      results BIT NOT NULL)

INSERT INTO @Database1Table1
  (number,
   CFG,
   Name) 
VALUES
  ('A123',
   '28A',
   N'tom'),
  ('B123',
   '23C',
   N'sindy'),
  ('C123',
   '35X',
   N'no matching sample')

INSERT INTO @Database2Table2
  (ITEM,
   results) 
VALUES
  ('28A',
   1),
  ('23C',
   0)

SELECT d1.number,
      d1.CFG,
      d2.ITEM,
      d2.results
FROM   @Database1Table1 AS d1
INNER JOIN @Database2Table2 AS d2 ON d1.CFG = d2.ITEM
--WHERE  d1.number = 'A123'

With Where clause you get:

number  CFG     ITEM    results
A123    28A     28A     1

without:

number  CFG     ITEM    results
A123    28A     28A     1
B123    23C     23C     0