t, Sql Server - rextester

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CREATE TABLE LinkStockEquipment
    ([Stock ID] varchar(2), [Equipment ID] varchar(2), [Equipment Qty] int)
;
    
INSERT INTO LinkStockEquipment
    ([Stock ID], [Equipment ID], [Equipment Qty])
VALUES
    ('A1', 'E1', 5),
    ('A1', 'E2', 3),
    ('A2', 'E3', 4),
    ('A2', 'E4', 6),
    ('A3', 'E5', 2)
;

WITH tmpResult as (
    SELECT 
         [Stock ID],
         'Eqp ID ' + CAST(rn AS VARCHAR(16)) as label,
         [Equipment ID] as [Value]
    FROM ( SELECT *, row_number() over (partition by [Stock ID] ORDER BY [Equipment ID]) as rn
           FROM LinkStockEquipment ) as rows
    
    UNION ALL
    
    SELECT 
         [Stock ID],
         'Eqp Qty ' + CAST(rn AS VARCHAR(16)) as label,
         CAST([Equipment Qty] AS VARCHAR(16))  as [Value]
    FROM ( SELECT *, row_number() over (partition by [Stock ID] ORDER BY [Equipment ID]) as rn
           FROM LinkStockEquipment ) as rows

)    
SELECT [Stock ID], 
       [Eqp ID 1], [Eqp Qty 1],
       [Eqp ID 2], [Eqp Qty 2]       
FROM   ( SELECT * FROM tmpResult ) as x
PIVOT ( 
        max( [Value] ) 
        for label in  ( [Eqp ID 1], [Eqp Qty 1], [Eqp ID 2], [Eqp Qty 2] )
      ) as pvt

View schema
Execution time: 0,02 sec, rows selected: 3, rows affected: 5, absolute service time: 0,2 sec, absolute service time: 0,21 sec