I have 4 tables and I can use MS access version to join them together
It worked both in Access and SQL. However, can someone rewrite join in SQL version
Many thanks.
(This is MS Access version)
SELECT [something]
FROM TaxonomyCrosswalk tc RIGHT JOIN (TargetTerm tt RIGHT JOIN (SearchTermShort st RIGHT JOIN RTMMobileAppDataFINAL rm ON (st.ActionID = rm.ActionID)
AND (st.DeviceID = rm.DeviceID)) ON (tt.ActionID = rm.ActionID)
AND (tt.DeviceID = rm.DeviceID)) ON tc.Service = st.SearchTermShort;
I would write this using LEFT JOINs instead of RIGHT JOINs. This is usually what is intended:
SELECT [something]
FROM RTMMobileAppDataFINAL rm LEFT JOIN
TargetTerm tt
ON tt.DeviceID = rm.DeviceID AND
tt.ActionID = rm.ActionID LEFT JOIN
SearchTermShort st
ON st.ActionID = rm.ActionID AND
st.DeviceID = rm.DeviceID LEFT JOIN
TaxonomyCrosswalk tc
ON tc.Service = st.SearchTermShort;
There are some subtle differences in chains of LEFT JOINs versus RIGHT JOIN when intermediate tables are missing matches that are in the outer tables. However, this structure is usually what is intended.
You can rewrite it with LEFT JOINs & do table swapping :
SELECT [something]
FROM RTMMobileAppDataFINAL rm LEFT JOIN
SearchTermShort st
ON (st.ActionID = rm.ActionID) AND (st.DeviceID = rm.DeviceID) LEFT JOIN
TargetTerm tt
ON (tt.ActionID = rm.ActionID) AND (tt.DeviceID = rm.DeviceID) LEFT JOIN
TaxonomyCrosswalk tc
ON tc.Service = st.SearchTermShort;
Related
I have this multi join query, is there any way to reduce the number of joins? Or maybe to split the query to 2 parts but then still get the same result set?
Having too many joins makes the query execute very slowly and inefficently
SELECT
MD.EVENT_ID,
AUI.ATLAS_USER_ID,
EVENT_TIME,
EVENT_TYPE,
INTERACTION_TOKEN,
CC.COUNTRY_CODE,
AP.ADV_PROJECT_ID, AP.ADV_PROJECT_NAME,
AC.ADV_CAMPAIGN_ID,
ADV_CAMPAIGN_NAME,
PC.PRT_CAMPAIGN_ID, PC.PRT_CAMPAIGN_NAME,
IP.IP_ADDRESS,
OS.OS,
BR.BROWSER,
FU.FULL_USER_AGENT,
RAW_ACTION_ID,
SE.SELLER_NETWORK_ID,
RIURL.RAW_INPUT as URL,
RIREF.RAW_INPUT as REF_URL,
MVG1.MAP_VALUE as TABOOLA ,
MVG2.MAP_VALUE as APPNEXUS ,
MVG3.MAP_VALUE as ETAG ,
MVG4.MAP_VALUE as FACEBOOK ,
MVG5.MAP_VALUE as MEDIAMATH ,
MVG6.MAP_VALUE as COOKIEID ,
MVG7.MAP_VALUE as IDFA ,
MVG8.MAP_VALUE as ADVLOGIN ,
MVG9.MAP_VALUE as OPENX ,
MVG10.MAP_VALUE as ADTRUTH ,
MVG11.MAP_VALUE as GOOGLE ,
MVG12.MAP_VALUE as ANDROID_ADV_ID ,
MVG13.MAP_VALUE as SDGUPI ,
MVG15.MAP_VALUE as RMX
FROM
EVENT_124_2 BASE
INNER JOIN
atlas__atlas_events MD ON BASE.EVENT_ID = MD.EVENT_ID
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG1 ON MVG1.MAP_VALUE_GK = BASE.TABOOLA_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG2 ON MVG2.MAP_VALUE_GK = BASE.APPNEXUS_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG3 ON MVG3.MAP_VALUE_GK = BASE.ETAG_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG4 ON MVG4.MAP_VALUE_GK = BASE.FACEBOOK_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG5 ON MVG5.MAP_VALUE_GK = BASE.MEDIAMATH_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG6 ON MVG6.MAP_VALUE_GK = BASE.COOKIEID_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG7 ON MVG7.MAP_VALUE_GK = BASE.IDFA_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG8 ON MVG8.MAP_VALUE_GK = BASE.ADVLOGIN_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG9 ON MVG9.MAP_VALUE_GK = BASE.OPENX_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG10 ON MVG10.MAP_VALUE_GK = BASE.ADTRUTH_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG11 ON MVG11.MAP_VALUE_GK = BASE.GOOGLE_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG12 ON MVG12.MAP_VALUE_GK = BASE.ANDROID_ADV_ID_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG13 ON MVG13.MAP_VALUE_GK = BASE.SDGUPI_HASH
LEFT JOIN
LOOKUP_STG__MAP_VALUE MVG15 ON MVG15.MAP_VALUE_GK = BASE.RMX_HASH
LEFT JOIN
LOOKUP_STG__ATLAS_USER_ID AUI ON AUI.ATLAS_USER_ID_GK = MD.ATLAS_USER_ID
LEFT JOIN
GAYA__ADV_PROJECTS AP ON AP.ADV_PROJECT_ID = MD.ADV_PROJECT_ID
LEFT JOIN
GAYA__ADV_CAMPAIGNS AC ON AC.ADV_CAMPAIGN_ID = MD.ADV_CAMPAIGN_ID
LEFT JOIN
GAYA__PRT_CAMPAIGNS PC ON PC.PRT_CAMPAIGN_ID = MD.PRT_CAMPAIGN_ID
LEFT JOIN
LOOKUP_STG__RAW_INPUT RIURL ON RIURL.RAW_INPUT_GK = BASE.URL_HASH
LEFT JOIN
LOOKUP_STG__RAW_INPUT RIREF ON RIREF.RAW_INPUT_GK = BASE.REF_HASH
LEFT JOIN
LOOKUP_STG__OS OS ON OS.OS_GK = MD.COUNTRY_CODE
LEFT JOIN
LOOKUP_STG__COUNTRY_CODE CC ON CC.COUNTRY_CODE_GK = MD.COUNTRY_CODE
LEFT JOIN
LOOKUP_STG__BROWSER BR ON BR.BROWSER_GK = MD.BROWSER
LEFT JOIN
LOOKUP_STG__IP_ADDRESS IP ON IP.IP_ADDRESS_GK = MD.IP_ADDRESS
LEFT JOIN
LOOKUP_STG__SELLER_NETWORK_ID SE ON SE.SELLER_NETWORK_ID_GK = MD.SELLER_NETWORK_ID
LEFT JOIN
LOOKUP_STG__FULL_USER_AGENT FU ON FU.FULL_USER_AGENT_GK = MD.FULL_USER_AGENT
;
Do you have any indexes on your key columns? You might try to put bitmap indexes on each key column in the main fact table and also in the dimension tables. That should give you a considerable speedup.
You say that the number of joins makes the query inefficient. But what you should be looking at is whether the tables that are joined with have the proper indexes in them. You obviously need all those fields from the tables you join with, so you can't simply not join with them.
For every JOIN you make in the query, verify that there exists an INDEX on the field that is joined with. For instance:
INNER JOIN
atlas__atlas_events MD ON BASE.EVENT_ID = MD.EVENT_ID
Does the table atlas__atlas_events have an INDEX on the EVENT_ID column?
You need to verify this for every such JOIN in your query. If such an INDEX does not exist you should create one.
If you execute this query in SQL Server Management Studio and include the actual execution plan, you will probably already see indications that you are missing indexes.
I'm trying to pass this query to inner join, but it does not know how?
This is the query I want to use InnerJoin with these values where
SELECT
ticket.id_ticket,
ticket.id_rede,
historico.id_historico,
historico.id_ticket,
centro.id_centro,
eqpto.id_eqpto,
eqpto.nome,
centro.sigla_centro,
interface.id_interface,
interface.id_eqpto,
interface.desig,
tecnologia.descricao,
interface.id_tecnologia,
tecnologia.id_tecnologia,
eqpto.id_centro,
eqpto.id_rede
FROM
app_gpa_ticket.ticket,
app_gpa_ticket.historico,
dados_v3.centro,
dados_v3.eqpto,
dados_v3.interface,
dados_v3.tecnologia
WHERE
ticket.id_ticket = historico.id_ticket AND
centro.id_centro = eqpto.id_centro AND
eqpto.id_eqpto = interface.id_eqpto AND
eqpto.id_rede = ticket.id_rede AND
tecnologia.id_tecnologia = interface.id_tecnologia;
Thank you!
I think you are trying to go to the standard (explicit) syntax. What you need to do is take what would be your JOIN operators in the WHERE clause and move them near the table itself. What you need to know is what tables on the left (Before the INNER JOIN operator you are joining to the right (After the INNER JOIN operator)
SELECT
ticket.id_ticket,
ticket.id_rede,
historico.id_historico,
historico.id_ticket,
centro.id_centro,
eqpto.id_eqpto,
eqpto.nome,
centro.sigla_centro,
interface.id_interface,
interface.id_eqpto,
interface.desig,
tecnologia.descricao,
interface.id_tecnologia,
tecnologia.id_tecnologia,
eqpto.id_centro,
eqpto.id_rede
FROM app_gpa_ticket.ticket
INNER JOIN app_gpa_ticket.historico ON ticket.id_ticket = historico.id_ticket
INNER JOIN dados_v3.eqpto ON eqpto.id_rede = ticket.id_rede
INNER JOIN dados_v3.interface ON eqpto.id_eqpto = interface.id_eqpto
INNER JOIN dados_v3.centro ON centro.id_centro = eqpto.id_centro
INNER JOIN dados_v3.tecnologia ON tecnologia.id_tecnologia = interface.id_tecnologia
I have been using Oracle SQL for around 6 months so still a beginner. I need to query the database to get information on all items on a particular order (order number is via $_GET['id']).
I have come up with the below query, it works as expected and as I need but I do not know whether I am over complicating things which would slow the query down at all. I understand there are a number of ways to do a single thing and there may be better methods to write this query since I am a beginner.
I am using Oracle 8i (due to this is the version an application we use is supplied with) so I believe that some JOIN etc. are not available in this version, but is there a better way to write a query such as the below?
SELECT auf_pos.auf_pos,
(SELECT auf_stat.anz
FROM auf_stat
WHERE auf_stat.auf_pos = auf_pos.auf_pos
AND auf_stat.auf_nr = ".$_GET['id']."),
(SELECT auf_text.zl_str
FROM auf_text
WHERE auf_text.zl_mod = 0
AND auf_text.auf_pos = auf_pos.auf_pos
AND auf_text.auf_nr = ".$_GET['id']."),
(SELECT glas_daten_basis.gl_bez
FROM glas_daten_basis
WHERE glas_daten_basis.idnr = auf_pos.glas1),
(SELECT lzr_daten.lzr_breite
FROM lzr_daten
WHERE lzr_daten.lzr_idnr = auf_pos.lzr1),
(SELECT glas_daten_basis.gl_bez
FROM glas_daten_basis
WHERE glas_daten_basis.idnr = auf_pos.glas2),
auf_pos.breite,
auf_pos.hoehe,
auf_pos.spr_jn
FROM auf_pos
WHERE auf_pos.auf_nr = ".$_GET['id']."
Thanks in advance to any Oracle gurus that could help this beginner out!
You could rewrite it using joins. If your subselects aren't expected to return any NULL values, then you can use INNER JOINS:
SELECT auf_pos.auf_pos,
auf_stat.anz,
auf_text.zl_str,
glas_daten_basis.gl_bez,
lzr_daten.lzr_breite,
glas_daten_basis.gl_bez,
auf_pos.breite,
auf_pos.hoehe,
auf_pos.spr_jn
FROM auf_pos
INNER JOIN auf_stat ON auf_stat.auf_pos = auf_pos.auf_pos AND auf_stat.auf_nr = ".$_GET['id'].")
INNER JOIN auf_text ON auf_text.zl_mod = 0 AND auf_text.auf_pos = auf_pos.auf_pos AND auf_text.auf_nr = ".$_GET['id'].")
INNER JOIN glas_daten_basis ON glas_daten_basis.idnr = auf_pos.glas1
INNER JOIN lzr_daten ON lzr_daten.lzr_idnr = auf_pos.lzr1
INNER JOIN glas_daten_basis ON glas_daten_basis.idnr = auf_pos.glas2
Or if there are cases where you wouldn't have matches on all the tables, you could replace the INNER joins with LEFT OUTER joins:
SELECT auf_pos.auf_pos,
auf_stat.anz,
auf_text.zl_str,
glas_daten_basis.gl_bez,
lzr_daten.lzr_breite,
glas_daten_basis.gl_bez,
auf_pos.breite,
auf_pos.hoehe,
auf_pos.spr_jn
FROM auf_pos
LEFT OUTER JOIN auf_stat ON auf_stat.auf_pos = auf_pos.auf_pos AND auf_stat.auf_nr = ".$_GET['id'].")
LEFT OUTER JOIN auf_text ON auf_text.zl_mod = 0 AND auf_text.auf_pos = auf_pos.auf_pos AND auf_text.auf_nr = ".$_GET['id'].")
LEFT OUTER JOIN glas_daten_basis ON glas_daten_basis.idnr = auf_pos.glas1
LEFT OUTER JOIN lzr_daten ON lzr_daten.lzr_idnr = auf_pos.lzr1
LEFT OUTER JOIN glas_daten_basis ON glas_daten_basis.idnr = auf_pos.glas2
Whether or not you see any performance gains is debatable. As I understand it, the Oracle query optimizer should take your query and execute it with a similar plan to the join queries, but this is dependent on a number of factors, so the best thing to do it give it a try..
I am trying to execute the following sql query but it takes 22 seconds to execute. the number of returned items is 554192. I need to make this faster and have already put indexes in all the tables involved.
SELECT mc.name AS MediaName,
lcc.name AS Country,
i.overridedate AS Date,
oi.rating,
bl1.firstname + ' ' + bl1.surname AS Byline,
b.id BatchNo,
i.numinbatch ItemNumberInBatch,
bah.changedatutc AS BatchDate,
pri.code AS IssueNo,
pri.name AS Issue,
lm.neptunemessageid AS MessageNo,
lmt.name AS MessageType,
bl2.firstname + ' ' + bl2.surname AS SourceFullName,
lst.name AS SourceTypeDesc
FROM profiles P
INNER JOIN profileresults PR
ON P.id = PR.profileid
INNER JOIN items i
ON PR.itemid = I.id
INNER JOIN batches b
ON b.id = i.batchid
INNER JOIN itemorganisations oi
ON i.id = oi.itemid
INNER JOIN lookup_mediachannels mc
ON i.mediachannelid = mc.id
LEFT OUTER JOIN lookup_cities lc
ON lc.id = mc.cityid
LEFT OUTER JOIN lookup_countries lcc
ON lcc.id = mc.countryid
LEFT OUTER JOIN itembylines ib
ON ib.itemid = i.id
LEFT OUTER JOIN bylines bl1
ON bl1.id = ib.bylineid
LEFT OUTER JOIN batchactionhistory bah
ON b.id = bah.batchid
INNER JOIN itemorganisationissues ioi
ON ioi.itemorganisationid = oi.id
INNER JOIN projectissues pri
ON pri.id = ioi.issueid
LEFT OUTER JOIN itemorganisationmessages iom
ON iom.itemorganisationid = oi.id
LEFT OUTER JOIN lookup_messages lm
ON iom.messageid = lm.id
LEFT OUTER JOIN lookup_messagetypes lmt
ON lmt.id = lm.messagetypeid
LEFT OUTER JOIN itemorganisationsources ios
ON ios.itemorganisationid = oi.id
LEFT OUTER JOIN bylines bl2
ON bl2.id = ios.bylineid
LEFT OUTER JOIN lookup_sourcetypes lst
ON lst.id = ios.sourcetypeid
WHERE p.id = #profileID
AND b.statusid IN ( 6, 7 )
AND bah.batchactionid = 6
AND i.statusid = 2
AND i.isrelevant = 1
when looking at the execution plan I can see an step which is costing 42%. Is there any way I could get this to a lower threshold or any way that I can improve the performance of the whole query.
Remove the profiles table as it is not needed and change the WHERE clause to
WHERE PR.profileid = #profileID
You have a left outer join on the batchactionhistory table but also have a condition in your WHERE clause which turns it back into an inner join. Change you code to this:
LEFT OUTER JOIN batchactionhistory bah
ON b.id = bah.batchid
AND bah.batchactionid = 6
You don't need the batches table as it is used to join other tables which could be joined directly and to show the id in you SELECT which is also available in other tables. Make the following changes:
i.batchidid AS BatchNo,
LEFT OUTER JOIN batchactionhistory bah
ON i.batchidid = bah.batchid
Are any of the fields that are used in joins or the WHERE clause from tables that contain large amounts of data but are not indexed. If so try adding an index on at time to the largest table.
Do you need every field in the result - if you could loose one or to you maybe could reduce the number of tables further.
First, if this is not a stored procedure, make it one. That's a lot of text for sql server to complile.
Next, my experience is that "worst practices" are occasionally a good idea. Specifically, I have been able to improve performance by splitting large queries into a couple or three small ones and assembling the results.
If this query is associated with a .net, coldfusion, java, etc application, you might be able to do the split/re-assemble in your application code. If not, a temporary table might come in handy.
I'm currently migrating a customers application from ColdFusion on Windows with SQL Server to ColdFusion on Linux with MySQL and I'm running into some issues recreating their views with regards to joins.
Can anyone help me work out how the following should be converted.
SELECT
<columns>
FROM assetType
INNER JOIN assets
INNER JOIN AssetToContent ON assets.asset_id = AssetToContent.asset_id
ON assetType.asset_typeID = assets.asset_typeID
RIGHT OUTER JOIN ContentType
INNER JOIN Content ON ContentType.ContentTypeID = Content.ContentTypeID
ON AssetToContent.ContentID = Content.ContentID
LEFT OUTER JOIN Page_Content ON Content.ContentID = Page_Content.ContentID
RIGHT OUTER JOIN Page ON Page_Content.PID = Page.PID
The INNER JOIN's without an ON clause are what are tripping me up and I can't find any good SQL Server docs on the ordering of nested joins.
This should work. I don't know what voodoo syntax SQL Server uses, but your ON clauses were all over the place:
SELECT
<columns>
FROM assetType
INNER JOIN assets ON assetType.asset_typeID = assets.asset_typeID
INNER JOIN AssetToContent ON assets.asset_id = AssetToContent.asset_id
INNER JOIN Content ON AssetToContent.ContentID = Content.ContentID
RIGHT OUTER JOIN ContentType ON ContentType.ContentTypeID = Content.ContentTypeID
LEFT OUTER JOIN Page_Content ON Content.ContentID = Page_Content.ContentID
RIGHT OUTER JOIN Page ON Page_Content.PID = Page.PID