data of 1 stu is in 3 rows i want in 1 row in sql

Hello jihok,

Please use this query and you can convert your result, 

WITH RankedSubjects AS (
    SELECT
        STU,
        SUB,
        ROW_NUMBER() OVER (PARTITION BY STU ORDER BY SUB) AS RowNum
    FROM
        YourTable
)
SELECT
    STU,
    [1] AS SUB1,
    [2] AS SUB2,
    [3] AS SUB3
FROM
    RankedSubjects
PIVOT (
    MAX(SUB) FOR RowNum IN ([1], [2], [3])
) AS PivotTable;

Try this:

SELECT STU, [MAT] AS SUB1, [CHEM] AS SUB2, [PHY] AS SUB3
FROM (SELECT STU, SUB FROM your_table_name) AS SourceTable
PIVOT (MAX(SUB) FOR SUB IN ([MAT], [CHEM], [PHY])) AS PivotTable;