How do I include records in a Summary query to include those that don't have data? - sql

Question

I have a query on a transaction table that returns the Summarized total on a column for each ID based on a data range. The query works great except it doesn't include those IDs that don't have data in the transaction table. How can I include those IDs in my result filled with a zero total. Here's a simplified version of my query.
SELECT tblID.IDName
,SUM(CASE
WHEN tblTransactions.idxTransType = 30
THEN CAST(tblTransactions.TimeAmount AS FLOAT) / 60.0
ELSE 0
END) AS 'Vacation'
FROM tblTransactions
INNER JOIN tblTransTypes ON tblTransactions.idxTransType = tblTransTypes.IdxTransType
INNER JOIN tblID ON tblTransactions.idxID = tblID.IdxID
WHERE (tblTransactions.Deleted = 0)
AND (tblTransactions.NotCurrent = 0)
AND (tblTransactions.TransDate >= CONVERT(DATETIME, 'March 1, 2018', 102))
AND (tblTransactions.TransDate <= CONVERT(DATETIME, 'April 11, 2018', 102))
GROUP BY tblID.IDName

Answer 1

Actually it's slightly more complicated than that:
SELECT
i.IDName,
SUM(CASE WHEN t.idxTransType = 30 THEN CAST(t.TimeAmount AS FLOAT) / 60.0 ELSE 0 END) AS 'Vacation'
FROM
tblID i
LEFT JOIN tblTransactions t ON t.idxID = i.IdxID AND t.Deleted = 0 AND t.NotCurrent = 0 AND t.TransDate BETWEEN '20180301' AND '20180411'
LEFT JOIN tblTransTypes tt ON tt.IdxTransType = t.idxTransType
GROUP BY
i.IDName;

Answer 2

You want left joins:
SELECT i.IDName,
SUM(CASE WHEN t.idxTransType = 30 THEN CAST(t.TimeAmount AS Float) / 60.0 ELSE 0 END) AS Vacation
FROM tblID i LEFT JOIN
tblTransactions t
ON t.idxID = i.IdxID AND
t.Deleted = 0 AND
t.NotCurrent = 0 AND
t.TransDate >= '2018-03-01' AND
t.TransDate <= '2018-04-11'
tblTransTypes tt
ON t.idxTransType = tt.IdxTransType
GROUP BY i.IDName;
Notes:
Table aliases make the query much easier to write and to read.
Use ISO/ANSI standard date formats.
The filter conditions on all but the first table belong in the ON clauses.