How to write these code in sql

Transact-SQL
1

Capture

2 
USE harish_sample 

go 

DROP TABLE dog 

go 

CREATE TABLE dog 
  ( 
     NAME  VARCHAR(100), 
     qty   INT, 
     color VARCHAR(100) 
  ) 

go 

INSERT INTO dog 
SELECT 'LALA', 
       3, 
       'BLACK' 

INSERT INTO dog 
SELECT 'LALA', 
       4, 
       'WHITE' 

INSERT INTO dog 
SELECT 'LALA', 
       5, 
       'WHITE' 

go 

SELECT * 
FROM   dog 

go

SELECT ( (SELECT Sum(qty)
FROM dog
WHERE color = 'WHITE') - (SELECT Sum(qty)
FROM dog
WHERE color = 'BLACK') )

3

You can do this with a single group by:

Declare @dog Table (name varchar(100), Qty int, Color varchar(10));

 Insert Into @dog (name, Qty, color)
 Values ('LALA', 3, 'BLACK')
      , ('LALA', 4, 'WHITE')
      , ('LALA', 5, 'WHITE');

 Select *
   From @dog;

 Select name
      , Total = sum(iif(d.Color = 'BLACK', -1, 1) * d.Qty)
   From @dog    d
  Group By
        name;

The condition will force the values for BLACK to be negative - and all other values to be positive.