Joins +ABAP Query

Question

Dear ALL,
When we will use joins in internal table example joining or two or more  table.
And Explain abt ABAP Query.
Regards
Vikas

Answer 1

Hi
Syntax
... [(] {dbtab_left [AS tabalias_left]} | join
{[INNER] JOIN}|{LEFT [OUTER] JOIN}
{dbtab_right [AS tabalias_right] ON join_cond} [)] ... .
Effect
The join syntax represents a recursively nestable join expression. A join expression consists of a left-hand and a right- hand side, which are joined either by means of [INNER] JOIN or LEFT [OUTER] JOIN . Depending on the type of join, a join expression can be either an inner ( INNER) or an outer (LEFT OUTER) join. Every join expression can be enclosed in round brackets. If a join expression is used, the SELECT command circumvents SAP buffering.
On the left-hand side, either a single database table, a view dbtab_left, or a join expression join can be specified. On the right-hand side, a single database table or a view dbtab_right as well as join conditions join_cond can be specified after ON. In this way, a maximum of 24 join expressions that join 25 database tables or views with each other can be specified after FROM.
AS can be used to specify an alternative table name tabalias for each of the specified database table names or for every view. A database table or a view can occur multiple times within a join expression and, in this case, have various alternative names.
The syntax of the join conditions join_cond is the same as that of the sql_cond conditions after the addition WHERE, with the following differences:
At least one comparison must be specified after ON.
Individual comparisons may be joined using AND only.
All comparisons must contain a column in the database table or the view dbtab_right on the right-hand side as an operand.
The following language elements may not be used: BETWEEN, LIKE, IN.
No sub-queries may be used.
For outer joins, only equality comparisons (=, EQ) are possible.
If an outer join occurs after FROM, the join condition of every join expression must contain at least one comparison between columns on the left-hand and the right-hand side.
In outer joins, all comparisons that contain columns as operands in the database table or the view dbtab_right on the right-hand side must be specified in the corresponding join condition. In the WHERE condition of the same SELECT command, these columns are not allowed as operands.
Resulting set for inner join
The inner join joins the columns of every selected line on the left- hand side with the columns of all lines on the right-hand side that jointly fulfil the join_cond condition. A line in the resulting set is created for every such line on the right-hand side. The content of the column on the left-hand side may be duplicated in this case. If none of the lines on the right-hand side fulfils the join_cond condition, no line is created in the resulting set.
Resulting set for outer join
The outer join basically creates the same resulting set as the inner join, with the difference that at least one line is created in the resulting set for every selected line on the left-hand side, even if no line on the right-hand side fulfils the join_cond condition. The columns on the right-hand side that do not fulfil the join_cond condition are filled with null values.
Example
Join the columns carrname, connid, fldate of the database tables scarr, spfli and sflight by means of two inner joins. A list is created of the flights from p_cityfr to p_cityto. Alternative names are used for every table.
PARAMETERS: p_cityfr TYPE spfli-cityfrom,
p_cityto TYPE spfli-cityto.
DATA: BEGIN OF wa,
fldate TYPE sflight-fldate,
carrname TYPE scarr-carrname,
connid TYPE spfli-connid,
END OF wa.
DATA itab LIKE SORTED TABLE OF wa
WITH UNIQUE KEY fldate carrname connid.
SELECT ccarrname pconnid f~fldate
INTO CORRESPONDING FIELDS OF TABLE itab
FROM ( ( scarr AS c
INNER JOIN spfli AS p ON pcarrid = ccarrid
AND p~cityfrom = p_cityfr
AND p~cityto = p_cityto )
INNER JOIN sflight AS f ON fcarrid = pcarrid
AND fconnid = pconnid ).
LOOP AT itab INTO wa.
WRITE: / wa-fldate, wa-carrname, wa-connid.
ENDLOOP.
Example
Join the columns carrid, carrname and connid of the database tables scarr and spfli using an outer join. The column connid is set to the null value for all flights that do not fly from p_cityfr. This null value is then converted to the appropriate initial value when it is transferred to the assigned data object. The LOOP returns all airlines that do not fly from p_cityfr.
PARAMETERS p_cityfr TYPE spfli-cityfrom.
DATA: BEGIN OF wa,
carrid TYPE scarr-carrid,
carrname TYPE scarr-carrname,
connid TYPE spfli-connid,
END OF wa,
itab LIKE SORTED TABLE OF wa
WITH NON-UNIQUE KEY carrid.
SELECT scarrid scarrname p~connid
INTO CORRESPONDING FIELDS OF TABLE itab
FROM scarr AS s
LEFT OUTER JOIN spfli AS p ON scarrid = pcarrid
AND p~cityfrom = p_cityfr.
LOOP AT itab INTO wa.
IF wa-connid = '0000'.
WRITE: / wa-carrid, wa-carrname.
ENDIF.
ENDLOOP.
Query
http://help.sap.com/saphelp_46c/helpdata/en/35/26b413afab52b9e10000009b38f974/content.htm
http://www.thespot4sap.com/Articles/SAP_ABAP_Queries_Introduction.asp
Step-by-step guide for creating ABAP query
http://www.sappoint.com/abap/ab4query.pdf
ABAP query is mostly used by functional consultants.
SAP Query
Purpose
The SAP Query application is used to create lists not already contained in the SAP standard system. It has been designed for users with little or no knowledge of the SAP programming language ABAP. SAP Query offers users a broad range of ways to define reporting programs and create different types of reports such as basic lists, statistics, and ranked lists.
Features
SAP Query's range of functions corresponds to the classical reporting functions available in the system. Requirements in this area such as list, statistic, or ranked list creation can be met using queries.
All the data required by users for their lists can be selected from any SAP table created by the customer.
To define a report, you first have to enter individual texts, such as titles, and select the fields and options which determine the report layout. Then you can edit list display in WYSIWYG mode whenever you want using drag and drop and the other toolbox functions available.
ABAP Query, as far as I Believe, is the use of select statements in the ABAP Programming. This needs a knowledge of Open SQL commands like Select,UPdtae, Modify etc. This has to be done only by someone who has a little bit of ABAP experience.
To sum up, SAP queries are readymade programs given by SAP, which the user can use making slight modification like the slection texts, the tables from which the data is to be retrieved and the format in which the data is to be displayed.ABAP queries become imperative when there is no such SAP query existing and also when there is a lot of customizing involved to use a SAP Query directly
use either SQ02 ans SQ01
or SQVI tr code
for more information please go thru this url:
http://www.thespot4sap.com/Articles/SAP_ABAP_Queries_Create_The_Query.asp
http://goldenink.com/abap/sap_query.html
Please check this PDF document (starting page 352) perhaps it will help u.
http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCSRVQUE/BCSRVQUE.pdf
check the below link will be helpful for u
Tutorial on SQVI
once you create query system generates a report starting with AQZZ/SAPQUERY/ABAGENCY2======= assing this report to tr code for the same
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Regards
Anji