SQL SELECT from third level table - sql

Ok I know little about SQL so bear with me...
I'm trying to see if certain values exist in a third level table and I don't know how to go about it. Here is the scenario...
I have a Accident table that holds accident information. It has 3 one-to-many child tables (Units, Occupants, NonMotorists). An each of those child tables have their own many-to-many child table (Alcohol). I need to be able to have some way of seeing if a range of values exists in a field in those Alcohol tables. Here is watered down version of what my structure for the tables looks like...
--tblAccident--_
PK_AccidentNumber
--tblAccidentUnit--
PK_PrimaryKey
FK_AccidentNumber
--tblAccidentOccupant--
PK_PrimaryKey
FK_AccidentNumber
--tblAccidentNonMotorist--
PK_PrimaryKey
FK_AccidentNumber
--tblAccidentUnitAlcohol--
PK_PrimaryKey
FK_ForeignKey
AlcoholValue <---- THIS IS WHAT I NEED TO SEARCH
--tblAccidentOccupantAlcohol--
PK_PrimaryKey
FK_ForeignKey
AlcoholValue <---- THIS IS WHAT I NEED TO SEARCH
--tblAccidentNonMotoristAlcohol--
PK_PrimaryKey
FK_ForeignKey
AlcoholValue <---- THIS IS WHAT I NEED TO SEARCH
I hope this makes some sense as to what i am trying to accomplish. thank you

I assume you just want to get info from the third level table if the range exists.
Try the query given below:
Since the database is not specified am not sure if the BETWEEN operator in your database would includes the test values.
SELECT AccidentNumber, 'AccidentUnit' AS TableFound, c.PrimaryKey AS TableKeyValue
FROM tblAccident a INNER JOIN tblAccidentUnit b
ON a.AccidentNumber = b.AccidentNumber INNER JOIN tblAccidentUnitAlcohol c
ON b.PrimaryKey = c.ForeignKey
AND c.AlcoholValue BETWEEN <RANGE_START> AND <RANGE_END>
UNION
SELECT AccidentNumber, 'AccidentOccupant' AS TableFound, c.PrimaryKey AS TableKeyValue
FROM tblAccident a INNER JOIN tblAccidentOccupant b
ON a.AccidentNumber = b.AccidentNumber INNER JOIN tblAccidentOccupantAlcohol c
ON b.PrimaryKey = c.ForeignKey
AND c.AlcoholValue BETWEEN <RANGE_START> AND <RANGE_END>
UNION
SELECT AccidentNumber, 'AccidentNonMotorist' AS TableFound, c.PrimaryKey AS TableKeyValue
FROM tblAccident a INNER JOIN tblAccidentNonMotorist b
ON a.AccidentNumber = b.AccidentNumber INNER JOIN tblAccidentNonMotoristAlcohol c
ON b.PrimaryKey = c.ForeignKey
AND c.AlcoholValue BETWEEN <RANGE_START> AND <RANGE_END>

Related

How to include column values as null even when condition is not met?

Write a query to show ALL building names, their metering company name and meter type for all buildings that do not have postpaid meters.
The image 1 is the result that I should get and image 2 is the results that i am getting:
USE Ultimate_DataBase
GO
SELECT [Bld_Name], [Elec_company_name], [Mtype_Name]
FROM [dbo].[Metering_Company] A
FULL OUTER JOIN [dbo].[Metering_Type] D
ON A.[MType_ID]= D.MType_ID
FULL OUTER JOIN [dbo].[Building_metering] B
ON A.[Elec_ID]= B.[Elec_ID]
FULL OUTER JOIN [dbo].[Building] C
ON C.[Bld_ID]= B.[Bld_ID]
WHERE [Mtype_Name] != 'POSTPAID'
Try moving the WHERE logic to the corresponding ON clause:
SELECT [Bld_Name], [Elec_company_name], [Mtype_Name]
FROM [dbo].[Metering_Company] A
FULL OUTER JOIN [dbo].[Metering_Type] D
ON A.[MType_ID]= D.MType_ID AND
[Mtype_Name] != 'POSTPAID' -- change is here
FULL OUTER JOIN [dbo].[Building_metering] B
ON A.[Elec_ID]= B.[Elec_ID]
FULL OUTER JOIN [dbo].[Building] C
ON C.[Bld_ID]= B.[Bld_ID];
Note: Please add aliases to your select clause. They are not mandatory, assuming no two tables ever have columns by the same name, but just having aliases would have made your question easier to answer.
FULL JOIN isn't seem necessary -- in fact FULL JOIN is almost never needed, and especially not for routine JOINs in a well-structured database.
The structure of the question suggests NOT EXISTS:
SELECT b.*
FROM dbo.Building b
WHERE NOT EXISTS (SELECT 1
FROM dbo.Building_metering bm JOIN
dbo.Metering_Company mc
ON bm.Elec_ID = mc.Elec_ID JOIN
dbo.Metering_Type mt
ON mt.MType_ID = mc.MType_ID
WHERE bm.Bld_ID = b.Bld_ID AND mt.Mtype_Name = 'POSTPAID'
);
You can also express this as a LEFT JOIN and filtering:
SELECT b.*
FROM dbo.Building b LEFT JOIN
dbo.Building_metering bm
ON bm.Bld_ID = b.Bld_ID LEFT JOIN
dbo.Metering_Company mc
ON bm.Elec_ID = mc.Elec_ID LEFT JOIN
dbo.Metering_Type mt
ON mt.MType_ID = mc.MType_ID AND
mt.Mtype_Name = 'POSTPAID'
WHERE mt.MType_ID IS NULL;
This allows you to select columns from any of the tables.
Notes:
FULL JOIN is almost never needed.
Use meaningful table aliases! Arbitrary letters mean nothing. Use table abbreviations.
Escaping column and table names with square braces just makes code harder to write and to read.
USE Ultimate_DataBase
GO
SELECT [Bld_Name], [Elec_company_name], [Mtype_Name]
FROM [dbo].[Metering_Company] A
LEFT JOIN [dbo].[Metering_Type] D
ON A.[MType_ID]= D.MType_ID
LEFT JOIN [dbo].[Building_metering] B
ON A.[Elec_ID]= B.[Elec_ID]
LEFT JOIN [dbo].[Building] C
ON C.[Bld_ID]= B.[Bld_ID]
Use this

Two SQL Queries With Some Overlapping Data

I'm trying to combine two different SQL queries into one table. I've tried various joins and Union but it either duplicates rows or doesn't show all of them.
The first query is
Select
HW.DisplayName,
HW.LocationDetails_0B39A057_2BE8_11B2_BBE2_1E03564AA5CA,
HW.Notes_5CFC0E2A_AB82_5830_D4BB_0596CBED1984
FROM MT_Cireson$AssetManagement$HardwareAsset HW
where HardwareAssetStatus_3019ADDF_4F3D_2C55_2024_72C22E11F4CF = '866879DF-8FB6-E521-F0E3-FEF86EE1BC92'
This gives all of my hardware assets that have the status I'm looking for.
The second query is:
SELECT
hw.DisplayName,
HW.LocationDetails_0B39A057_2BE8_11B2_BBE2_1E03564AA5CA,
HW.Notes_5CFC0E2A_AB82_5830_D4BB_0596CBED1984,
UB.UPN_7641DFF7_7A20_DC04_FC1C_B6FA8715DA02
FROM MT_Cireson$AssetManagement$HardwareAsset HW
inner join Relationship Rel on HW.BaseManagedEntityId = Rel.SourceEntityId
inner join RelationshipType RT on RT.RelationshipTypeId = Rel.RelationshipTypeId
inner join MT_Microsoft$AD$UserBase UB on UB.BaseManagedEntityId = Rel.TargetEntityId
where RT.RelationshipTypeName = 'Cireson.AssetManagement.HardwareAssetHasPrimaryUser'
and HardwareAssetStatus_3019ADDF_4F3D_2C55_2024_72C22E11F4CF = '866879DF-8FB6-E521-F0E3-FEF86EE1BC92'
This gives all of the hardware assets I'm looking for that have a primary user configured, but doesn't give the assets without a primary user. I'm not sure how to either A: combine the results just putting in NULL as a primary user for records that don't have one, or B: actually query all the assets at one time and include the primary user column.
I didn't write the second query and I'm not sure exactly how it works. I've tried doing union between the queries but that duplicates the rows because the first query already contains all the elements in the second.
Edit: The PrimaryUser comes from the MT_Microsoft$AD$UserBase table. I've tried adding another column to the first and just setting it as null like:
null as primaryUser,
How about a LEFT JOIN to include all records from HW that are not in UB:
SELECT
hw.DisplayName,
HW.LocationDetails_0B39A057_2BE8_11B2_BBE2_1E03564AA5CA,
HW.Notes_5CFC0E2A_AB82_5830_D4BB_0596CBED1984,
UB.UPN_7641DFF7_7A20_DC04_FC1C_B6FA8715DA02
FROM
MT_Cireson$AssetManagement$HardwareAsset HW
INNER JOIN
Relationship Rel
ON
HW.BaseManagedEntityId = Rel.SourceEntityId
INNER JOIN
RelationshipType RT
ON
RT.RelationshipTypeId = Rel.RelationshipTypeId
LEFT JOIN
MT_Microsoft$AD$UserBase UB
ON
UB.BaseManagedEntityId = Rel.TargetEntityId
WHERE
RT.RelationshipTypeName = 'Cireson.AssetManagement.HardwareAssetHasPrimaryUser'
AND HardwareAssetStatus_3019ADDF_4F3D_2C55_2024_72C22E11F4CF = '866879DF-8FB6-E521-F0E3-FEF86EE1BC92'
UPDATE:
If the null primary users is what you want, I would recraft the query like:
SELECT
hw.DisplayName,
HW.LocationDetails_0B39A057_2BE8_11B2_BBE2_1E03564AA5CA,
HW.Notes_5CFC0E2A_AB82_5830_D4BB_0596CBED1984,
UB.UPN_7641DFF7_7A20_DC04_FC1C_B6FA8715DA02
FROM
MT_Cireson$AssetManagement$HardwareAsset HW
LEFT JOIN
MT_Microsoft$AD$UserBase UB
ON
HW.BaseManagedEntityId = UB.SourceEntityId
INNER JOIN
RelationshipType RT
ON
RT.RelationshipTypeId = Rel.RelationshipTypeId
INNER JOIN
Relationship Rel
ON
UB.BaseManagedEntityId = Rel.TargetEntityId
WHERE
RT.RelationshipTypeName = 'Cireson.AssetManagement.HardwareAssetHasPrimaryUser'
AND HardwareAssetStatus_3019ADDF_4F3D_2C55_2024_72C22E11F4CF = '866879DF-8FB6-E521-F0E3-FEF86EE1BC92'
I LEFT JOIN'ed HW and UB tables.
As I said earlier, you'll have to tweak the joins. I would try a LEFT JOIN on all tables.
you have an extra column in your 1st query that's why you have duplicates in your union. I would suggest using CTE, there might be other better efficient solutions out there.
;WITH query1
AS
(
SELECT col1, col2
FROM table
),
query2 AS
(
SELECT col1, col2
FROM table
)
SELECT *
FROM cteTable1
UNION ALL
SELECT *
FROM cteTable2
WHERE NOT EXISTS(SELECT * FROM cteTable1 WHERE cteTable1.col1 = cteTable2.col2)

SQL - How to put a condition for which table is selected without left join

I have a flag in a table which value ( 1 for US, or 2 for Global) indicates if the data will be in Table A or Table B.
A solution that works is to left join both tables; however this slows down significantly the scripts (from less than a second to over 15 seconds).
Is there any other clever way to do this? an equivalent of
join TableA only if TableCore.CountryFlag = "US"
join TableB only if TableCore.CountryFlag = "global"
Thanks a lot for the help.
You can try using this approach:
-- US data
SELECT
YourColumns
FROM
TableCore
INNER JOIN TableA AS T ON TableCore.JoinColumn = T.JoinColumn
WHERE
TableCore.CountryFlag = 'US'
UNION ALL
-- Non-US Data
SELECT
YourColumns -- These columns must match in number and datatype with previous SELECT
FROM
TableCore
INNER JOIN TableB AS T ON TableCore.JoinColumn = T.JoinColumn
WHERE
TableCore.CountryFlag = 'global'
However, if the result is still slow, you might want to check if the TableCore table has a index on CountryFlag and JoinColumn, and TableA and TableB an index on JoinColumn.
The basic structure is:
select . . ., coalesce(a.?, b.?) as ?
from tablecore c left join
tablea a
on c.? = a.? and c.countryflag = 'US' left join
tableb b
on c.? b.? and c.counryflag = 'global';
This version of the query can take advantage of indexes on tablea(?) and tableb(?).
If you have a complex query, this portion is probably not responsible for the performance problem.

Nice way to query for cross table

I have 3 tables :
A(k1,A) B(k1,k2,B) and C(k2,C).
I want to filter all A that satisfy C.k2 condition. in this example, I must filter go through table B : filter all B that have same k1 attribute with A , and filter all C k2 attribute with B (that I have filtered before).
I have an ugly way to do this :
select * from A where k1 in (select * .....) // it looks ugly and hard to trace
I have though about using join function, but don't really know how to do this. Please tell me a best way for this query.
Thanks :)
Try this Query.
select * from A
join b on a.k1 = b.k1
join c on c.k2 = b.k2
Explanation for JOIN
It sounds pretty easy:
select * from A
join B on B.k1 = A.k1
join C on C.k2 = B.k2
If I'm reading your table structure correctly, the join logic would be like this:
SELECT *
FROM A
JOIN B
ON A.k1 = B.k1
JOIN C
ON B.k2 = C.k2
You could of course then specify in the SELECT which table you want values from, ie:
SELECT A.*,C.*
Or Limit results with WHERE ie:
WHERE C.C = 'something'
Using join to retrieve data from two or more tables. see Join Fundamentals
SELECT A.k1,B.k2
FROM A
JOIN B ON A.k1 = B.k1
JOIN C ON B.k2 = C.k2

Alternatives to full outer join for logical OR in tree structure query

I hope the title is clear enough. I've been implementing logical AND/OR for tree structures which are kept in the database, using a simple nodes and a parent-child association table.
A sample tree has a structure like this:
A sample tree structure query is as follows:
The double lines in the query pattern mean that A has a child of type B (somewhere down its child nodes) OR C. I have implemented A -> HASCHILD -> C -> HASCHILD -> E with an inner join, and A -> HASCHILD -> B -> HASCHILD -> E is implemented like this.
The trick is joining these two branches on A. Since this is an OR operation, either B branch or C branch may not exist. The only method I could think of if to use full outer joins of two branches with A's node_id as the key. To avoid details, let me give this simplified snippet from my SQL query:
WITH A as (....),
B as (....),
C as (....),
......
SELECT *
from
A
INNER JOIN A_CONTAINS_B ON A.NODE_ID = A_CONTAINS_B.parent
INNER JOIN B ON A_CONTAINS_B.children #> ARRAY[B.NODE_ID]
INNER JOIN .....
full OUTER JOIN -- THIS IS WHERE TWO As ARE JOINED
(select
A2.NODE_ID AS A2_NODE_ID
from
A2
INNER JOIN A_CONTAINS_C ON A2.NODE_ID = C_CONTAINS_C.parent
INNER JOIN C ON A_CONTAINS_C.children #> ARRAY[C.NODE_ID]
INNER JOIN ....)
as other_branch
ON other_branch.A2_NODE_ID = A.NODE_ID
This query links two As which actually represent the same A using node_id, and if B or C does not exist, nothing breaks.
The result set has duplicates of course, but I can live with that. I can't however think of another way to implement OR in this context. ANDs are easy, they are inner joins, but left outer join is the only approach that lets me connect As. UNION ALL with dummy columns for both branches is not an option because I can't connect As in that case.
Do you have any alternatives to what I'm doing here?
UPDATE
TokenMacGuy's suggestion gives me a cleaner route than what I have at the moment. I should have remembered UNION.
Using the first approach he has suggested, I can apply a query pattern decomposition, which would be a consistent way of breaking down queries with logical operators. The following is a visual representation of what I'm going to do, just in case it helps someone else visualize the process:
This helps me do a lot of nice things, including creating a nice result set where query pattern components are linked to results.
I've deliberately avoided details of tables or other context, because my question is about how to join results of queries. How I handle the hierarchy in DB is a different topic which I'd like to avoid. I'll add more details into comments. This is basically an EAV table accomponied by a hierarchy table. Just in case someone would like to see it, here is the query I'm running without any simplifications, after following TokenMacGuy's suggestion:
WITH
COMPOSITION1 as (select comp1.* from temp_eav_table_global as comp1
WHERE
comp1.actualrmtypename = 'COMPOSITION'),
composition_contains_observation as (select * from parent_child_arr_based),
OBSERVATION as (select obs.* from temp_eav_table_global as obs
WHERE
obs.actualrmtypename = 'OBSERVATION'),
observation_cnt_element as (select * from parent_child_arr_based),
OBS_ELM as (select obs_elm.* from temp_eav_table_global as obs_elm
WHERE
obs_elm.actualrmtypename= 'ELEMENT'),
COMPOSITION2 as (select comp_node_tbl2.* from temp_eav_table_global as comp_node_tbl2
where
comp_node_tbl2.actualrmtypename = 'COMPOSITION'),
composition_contains_evaluation as (select * from parent_child_arr_based),
EVALUATION as (select eva_node_tbl.* from temp_eav_table_global as eva_node_tbl
where
eva_node_tbl.actualrmtypename = 'EVALUATION'),
eval_contains_element as (select * from parent_child_arr_based),
ELEMENT as (select el_node_tbl.* from temp_eav_table_global as el_node_tbl
where
el_node_tbl.actualrmtypename = 'ELEMENT')
select
'branch1' as branchid,
COMPOSITION1.featuremappingid as comprootid,
OBSERVATION.featuremappingid as obs_ftid,
OBSERVATION.actualrmtypename as obs_tn,
null as ev_ftid,
null as ev_tn,
OBS_ELM.featuremappingid as obs_elm_fid,
OBS_ELm.actualrmtypename as obs_elm_tn,
null as ev_el_ftid,
null as ev_el_tn
from
COMPOSITION1
INNER JOIN composition_contains_observation ON COMPOSITION1.featuremappingid = composition_contains_observation.parent
INNER JOIN OBSERVATION ON composition_contains_observation.children #> ARRAY[OBSERVATION.featuremappingid]
INNER JOIN observation_cnt_element on observation_cnt_element.parent = OBSERVATION.featuremappingid
INNER JOIN OBS_ELM ON observation_cnt_element.children #> ARRAY[obs_elm.featuremappingid]
UNION
SELECT
'branch2' as branchid,
COMPOSITION2.featuremappingid as comprootid,
null as obs_ftid,
null as obs_tn,
EVALUATION.featuremappingid as ev_ftid,
EVALUATION.actualrmtypename as ev_tn,
null as obs_elm_fid,
null as obs_elm_tn,
ELEMENT.featuremappingid as ev_el_ftid,
ELEMENT.actualrmtypename as ev_el_tn
from
COMPOSITION2
INNER JOIN composition_contains_evaluation ON COMPOSITION2.featuremappingid = composition_contains_evaluation.parent
INNER JOIN EVALUATION ON composition_contains_evaluation.children #> ARRAY[EVALUATION.featuremappingid]
INNER JOIN eval_contains_element ON EVALUATION.featuremappingid = eval_contains_element.parent
INNER JOIN ELEMENT on eval_contains_element.children #> ARRAY[ELEMENT.featuremappingid]
the relational equivalent to ∨ is &Union;. You could either use union to combine a JOIN b JOIN e with a JOIN c JOIN e or just use the union of b and c and join on the resulting, combined relation, something like a JOIN (b UNION c) JOIN e
More completely:
SELECT *
FROM a
JOIN (
SELECT
'B' source_relation,
parent,
b.child,
b_thing row_from_b,
NULL row_from_c
FROM a_contains_b JOIN b ON a_contains_b.child = b.node_id
UNION
SELECT
'C',
parent
c.child,
NULL,
c_thing
FROM a_contains_c JOIN c ON a_contains_c.child = c.node_id
) a_c ON A.NODE_ID = a_e.parent
JOIN e ON a_c.child = e.node_id;