MySQL 8.0

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CREATE TABLE `payData` (
  `payrunId` int(11) NOT NULL,
  `employeeId` int(11) NOT NULL,
  `category` varchar(100) CHARACTER SET latin1 COLLATE latin1_swedish_ci DEFAULT '',
  `value` int(11) NOT NULL
) ENGINE=InnoDB AUTO_INCREMENT=1344 DEFAULT CHARSET=latin1;

insert into `payData` values (2,121,'Repayment',2000);
insert into `payData` values (2,121,'Salary',15000);
insert into `payData` values (2,121,'Allowance',1000);

insert into `payData` values (2,122,'Salary',20000);
insert into `payData` values (2,122,'Allowance',2000);

SELECT 
    pi.employeeId,
    pi.payrunId,
    MAX(CASE
        WHEN pi.category = 'Repayment' THEN pi.value
        WHEN isnull(pi.category) = 1 then 0
        -- ELSE 0
    END) as 'Repayment',
     MAX(CASE
        WHEN pi.category = 'Salary' THEN pi.value
        ELSE 0
    END) as 'Salary',
     MAX(CASE
        WHEN pi.category = 'Allowance' THEN pi.value
        ELSE 0
    END) as 'Allowance'
FROM
   payData pi
GROUP BY pi.employeeId , pi.payrunId -- ,YEAR(pi.startDate) 
;

employeeId	payrunId	Repayment	Salary	Allowance
121	2	2000	15000	1000
122	2	null	20000	2000