Oracle 18c

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CREATE TABLE mydb ("DATE", meter, quality) AS
SELECT DATE '2022-08-01', 'MeterX', 42 FROM DUAL UNION ALL
SELECT DATE '2022-08-02', 'MeterX', 23 FROM DUAL UNION ALL
SELECT DATE '2022-08-04', 'MeterX',  7 FROM DUAL UNION ALL
SELECT DATE '2022-08-05', 'MeterX', 99 FROM DUAL;
4 rows affected

SELECT c.day,
       m.meter,
       COALESCE(m.quality, 0) AS quality
FROM   (
         SELECT DATE '2022-08-01' + (LEVEL - 1) AS day
         FROM   DUAL
         CONNECT BY DATE '2022-08-01' + (LEVEL - 1) <= DATE '2022-08-05'
       ) c
       LEFT OUTER JOIN MyDB m
       PARTITION BY (m.meter)
       ON (c.day <= m."DATE" and m."DATE" < c.day + 1)
WHERE  m.Meter = 'MeterX'
ORDER BY c.day;


DAY
METER
QUALITY


01-AUG-22
MeterX
42

02-AUG-22
MeterX
23

03-AUG-22
MeterX
0

04-AUG-22
MeterX
7

05-AUG-22
MeterX
99


SELECT c.day,
       m.meter,
       COALESCE(m.quality, 0) AS quality
FROM   (
         SELECT DATE '2022-08-01' + (LEVEL - 1) AS day
         FROM   DUAL
         CONNECT BY DATE '2022-08-01' + (LEVEL - 1) <= DATE '2022-08-05'
       ) c
       LEFT OUTER JOIN MyDB m
       ON (c.day <= m."DATE" and m."DATE" < c.day + 1 and m.Meter = 'MeterX')
ORDER BY c.day;


DAY
METER
QUALITY


01-AUG-22
MeterX
42

02-AUG-22
MeterX
23

03-AUG-22
null
0

04-AUG-22
MeterX
7

05-AUG-22
MeterX
99

DAY	METER	QUALITY
01-AUG-22	MeterX	42
02-AUG-22	MeterX	23
03-AUG-22	MeterX	0
04-AUG-22	MeterX	7
05-AUG-22	MeterX	99