Sunday, 1 May 2016

Interview Questions -- SQL Scenarios -- Part-2

Interview Questions -- SQL Scenarios -- Part-2

Scenario-3:   How to Swap 2 Column Values 
(OR) How to Interchange 2 Column Values
(OR) How to Update one column(CurrentFlag_Old) Values with another column(CurrentFlag_New)

Sample Scripts :- 
-- How to go inside into the Database
USE tempdb
GO
-- Create Table Variable
DECLARE @SampleTbl TABLE
(
   EmpID INT
  ,EmpName VARCHAR(50)
  ,CurrentFlag_Old BIT
  ,CurrentFlag_New BIT
)
-- INSERT Sample Data Into the Table Variable.
INSERT INTO @SampleTbl
SELECT 1,'Santhosh',0,1
UNION ALL
SELECT 2,'Kumari',1,0
UNION ALL
SELECT 3,'Kamesh',0,1
UNION ALL
SELECT 4,'Kavitha',1,1
UNION ALL
SELECT 5,'Lakshita',0,1


SELECT * FROM @SampleTbl


Expected Output :-  
Scenario-4:   How to Update 0(zero) with 1(One) and 1(One) with 0(zero) in CurrentFlag_New Column Using single Update Query.  

Expected Output :-  

Guys you can share your Query Through Comments.


5 comments:

  1. Scenario-3:
    Query:
    DECLARE @SampleTbl TABLE
    (
    EmpID INT
    ,EmpName VARCHAR(50)
    ,CurrentFlag_Old BIT
    ,CurrentFlag_New BIT
    )
    -- INSERT Sample Data Into the Table Variable.
    INSERT INTO @SampleTbl
    SELECT 1,'Santhosh',0,1
    UNION ALL
    SELECT 2,'Kumari',1,0
    UNION ALL
    SELECT 3,'Kamesh',0,1
    UNION ALL
    SELECT 4,'Kavitha',1,1
    UNION ALL
    SELECT 5,'Lakshita',0,1
    Update @SampleTbl
    Set
    CurrentFlag_Old=CurrentFlag_New,
    CurrentFlag_New=CurrentFlag_Old
    SELECT * FROM @SampleTbl

    ReplyDelete
  2. Scenario-4:
    Query:
    DECLARE @SampleTbl TABLE
    (
    EmpID INT
    ,EmpName VARCHAR(50)
    ,CurrentFlag_Old BIT
    ,CurrentFlag_New BIT
    )
    -- INSERT Sample Data Into the Table Variable.
    INSERT INTO @SampleTbl
    SELECT 1,'Santhosh',0,1
    UNION ALL
    SELECT 2,'Kumari',1,0
    UNION ALL
    SELECT 3,'Kamesh',0,1
    UNION ALL
    SELECT 4,'Kavitha',1,1
    UNION ALL
    SELECT 5,'Lakshita',0,1
    Update @SampleTbl
    Set CurrentFlag_New = Case CurrentFlag_New
    When 1 Then 0 Else 1
    END
    SELECT * FROM @SampleTbl

    ReplyDelete
  3. Scenario-3:
    DECLARE @SampleTbl TABLE
    (
    EmpID INT
    ,EmpName VARCHAR(50)
    ,CurrentFlag_Old BIT
    ,CurrentFlag_New BIT
    )
    -- INSERT Sample Data Into the Table Variable.
    INSERT INTO @SampleTbl
    SELECT 1,'Santhosh',0,1
    UNION ALL
    SELECT 2,'Kumari',1,0
    UNION ALL
    SELECT 3,'Kamesh',0,1
    UNION ALL
    SELECT 4,'Kavitha',1,1
    UNION ALL
    SELECT 5,'Lakshita',0,1

    UPDATE @SampleTbl SET CurrentFlag_Old=CurrentFlag_New,CurrentFlag_New=CurrentFlag_Old

    SELECT * FROM @SampleTbl

    Scenario-4:
    DECLARE @SampleTbl TABLE
    (
    EmpID INT
    ,EmpName VARCHAR(50)
    ,CurrentFlag_Old BIT
    ,CurrentFlag_New BIT
    )
    -- INSERT Sample Data Into the Table Variable.
    INSERT INTO @SampleTbl
    SELECT 1,'Santhosh',0,1
    UNION ALL
    SELECT 2,'Kumari',1,0
    UNION ALL
    SELECT 3,'Kamesh',0,1
    UNION ALL
    SELECT 4,'Kavitha',1,1
    UNION ALL
    SELECT 5,'Lakshita',0,1

    UPDATE @SampleTbl SET CurrentFlag_Old=~CurrentFlag_Old,CurrentFlag_New=~CurrentFlag_New

    SELECT * FROM @SampleTbl

    ReplyDelete
  4. PART-2

    --SWAPPING COLUMN VALUES
    UPDATE SAMP
    SET CurrentFlag_Old =CurrentFlag_New
    , CurrentFlag_New = CurrentFlag_Old

    --To Update 0(zero) with 1(One) and 1(One) with 0(zero) in CurrentFlag_New Column Using single Update Query
    update samp
    SET CurrentFlag_Old = CASE WHEN CurrentFlag_Old = 0 THEN 1
    WHEN CurrentFlag_Old =1 THEN 0
    END
    ,CurrentFlag_New = CASE WHEN CurrentFlag_New =1 THEN 0
    WHEN CurrentFlag_New =0 THEN 1
    END

    ReplyDelete
  5. Scenario 3

    -----------------------------
    DECLARE @temp BIT
    DECLARE @SampleTbl TABLE
    (
    EmpID INT
    ,EmpName VARCHAR(50)
    ,CurrentFlag_Old BIT
    ,CurrentFlag_New BIT
    )
    -- INSERT Sample Data Into the Table Variable.
    INSERT INTO @SampleTbl
    SELECT 1,'Santhosh',0,1
    UNION ALL
    SELECT 2,'Kumari',1,0
    UNION ALL
    SELECT 3,'Kamesh',0,1
    UNION ALL
    SELECT 4,'Kavitha',1,1
    UNION ALL
    SELECT 5,'Lakshita',0,1
    update @SampleTbl set currentflag_old=@temp,@temp=CurrentFlag_New,CurrentFlag_new=CurrentFlag_Old
    select * from @SampleTbl

    ReplyDelete