Complex Query Limited SQL Knowledge - sql

Question

Im trying to write what I believe is a rather complicated SQL query but Im working with limited SQL knowledge. I have this query:
SELECT
analysisvalue.analysisid,
heatname,
analysistime,
sampletype,
grade,
productid,
element,
value
FROM
dbo.AnalysisValue
INNER JOIN
dbo.CAnalysis
ON
dbo.AnalysisValue.AnalysisID = dbo.CAnalysis.AnalysisID
WHERE
heatname = 'A7M0066'
ORDER BY
analysisvalue.analysisid ASC,
element
and this query:
SELECT
*
FROM
S_analysis
WHERE
heat_no = 'A7M0066'
I need to modify the second query to also include * from S_analysis WHERE heat_no = 'A7M0066' but also all records including those without that heat_no where analysis_datetime is between the analysis time of the last record from the first query and two hours that follow that time.
The S_analysis table structure for the second query is:
analysis_datetime(datetime, not null)
heat_no(varchar(7), not null)
comment(varchar(40), null)
Then about 30 other columns of type (real, null)
The table structure of AnalysisValue in the first query is:
AnalysisID(int, not null)
Element(char(9), not null)
Value(real, null)
The table structure of CAnalysis in the first query is:
AnalysisID(PK, int, not null)
HeatName(char(7), null)
AnalysisTime(datetime, null)
SampleType(char(5), null)
Grade(char(4), null)
ProductID(char(14), null)

Answer 1

Try this (never used sql-server, but it should produce your expected results)
SELECT
*
FROM
S_analysis
CROSS JOIN
(
SELECT TOP 1
analysistime
FROM
dbo.CAnalysis
WHERE
heatname = 'A7M0066'
ORDER BY
analysistime DESC ) c
WHERE
heat_no = 'A7M0066'
OR ( heat_no IS NULL AND s.analysis_datetime BETWEEN c.analysistime AND DATEADD(hh, 2, c.analysistime ) )

Answer 2

Since you need only top row from your 1st query .You can use Cross join with the 2nd query to get the desired result
;with cte as
(SELECT
analysisvalue.analysisid,
heatname,
analysistime,
sampletype,
grade,
productid,
element,
value
FROM
dbo.AnalysisValue
INNER JOIN
dbo.CAnalysis
ON
dbo.AnalysisValue.AnalysisID = dbo.CAnalysis.AnalysisID
WHERE
heatname = 'A7M0066'
)
SELECT
*
FROM
S_analysis s
CROSS JOIN (SELECT TOP 1 analysistime
FROM cte
ORDER BY analysisid desc
) c
WHERE s.heat_no = 'A7M0066' OR
(s.analysis_datetime BETWEEN c.analysistime AND DATEADD(hh, 2, c.analysistime ))