COLLECT : ABAP Keyword a day

COLLECT
Basic form
COLLECT [wa INTO] itab.
Addition
… SORTED BY f

Effect
COLLECT is used to create unique or compressed datsets. The key fields are the default key fields of the internal table itab .

If you use only COLLECT to fill an internal table, COLLECT makes sure that the internal table does not contain two entries with the same default key fields.

If, besides its default key fields, the internal table contains number fields (see also ABAP/4 number types ), the contents of these number fields are added together if the internal table already contains an entry with the same key fields.

If the default key of an internal table processed with COLLECT is blank, all the values are added up in the first table line.

If you specify wa INTO , the entry to be processed is taken from the explicitly specified work area wa . If not, it comes from the header line of the internal table itab .

After COLLECT , the system field SY-TABIX contains the index of the – existing or new – table entry with default key fields which match those of the entry to be processed.
Notes
COLLECT can create unique or compressed datasets and should be used precisely for this purpose. If uniqueness or compression are unimportant, or two values with identical default key field values could not possibly occur in your particular task, you should use APPEND instead. However, for a unique or compressed dataset which is also efficient, COLLECT is the statement to use.
If you process a table with COLLECT , you should also use COLLECT to fill it. Only by doing this can you guarantee that

* the internal table will actually be unique or compressed, as described above and
* COLLECT will run very efficiently.

If you use COLLECT with an explicitly specified work area, it must be compatible with the line type of the internal table.
Example
Compressed sales figures for each company

DATA: BEGIN OF COMPANIES OCCURS 10,
NAME(20),
SALES TYPE I,
END OF COMPANIES.
COMPANIES-NAME = ‘Duck’. COMPANIES-SALES = 10.
COLLECT COMPANIES.
COMPANIES-NAME = ‘Tiger’. COMPANIES-SALES = 20.
COLLECT COMPANIES.
COMPANIES-NAME = ‘Duck’. COMPANIES-SALES = 30.
COLLECT COMPANIES.

The table COMPANIES now has the following appearance:

NAME SALES
Duck 40
Tiger 20

Addition
… SORTED BY f
Effect
COLLECT … SORTED BY f is obsolete and should no longer be used. Use APPEND … SORTED BY f which has the same meaning.
Note
Performance

The cost of a COLLECT in terms of performance increases with the width of the default key needed in the search for table entries and the number of numeric fields with values which have to be added up, if an entry is found in the internal table to match the default key fields.
If no such entry is found, the cost is reduced to that required to append a new entry to the end of the table.

A COLLECT statement used on a table which is 100 bytes wide and has a key which is 60 bytes wide and seven numeric fields is about approx. 50 msn (standardized microseconds).
Note
Runtime errors

* COLLECT_OVERFLOW : Overflow in integer field when calculating totals.
* COLLECT_OVERFLOW_TYPE_P : Overflow in type P field when calculating totals.

Related APPEND , WRITE … TO , MODIFY , INSERT

———————
ABAPer, mail: abap.community@gmail.com http://www.erpdb.info

If you like this post, you may as well like these too:

1. AT : ABAP Keyword a day AT Events in lists- AT LINE-SELECTION.- AT USER-COMMAND.- AT PFn.Events on selection screens- AT SELECTION-SCREEN.Control break with extracts- AT NEW f.- AT END OF f.- AT FIRST.- AT LAST.- AT...
2. GET: ABAP Keyword a day GET: Event keyword for defining event blocks for reporting events. GET <node> [FIELDS <fi> <f 2>...]. GET node LATE [FIELDS f1 f2 ...]. Only occurs in executable programs. When the...
3. DO : ABAP Keyword a day DO Variants 1. DO. 2. DO n TIMES. Variant 1 DO. Addition … VARYING f FROM f1 NEXT f2 Effect Repeats the processing enclosed by the DO and ENDDO statements...
4. ASSIGN: ABAP Keyword a day ASSIGN Variants:1. ASSIGN f TO .2. ASSIGN (f) TO .3. ASSIGN TABLE FIELD (f) TO .4. ASSIGN LOCAL COPY OF MAIN TABLE FIELD (f) TO .5. ASSIGN COMPONENT idx OF...
5. FORM: ABAP Keyword a day FORM: Defines a subroutine. Syntax FORM [USING ... [VALUE(][)] [TYPE |LIKE ]„. ] [CHANGING... [VALUE(][)] [TYPE |LIKE ]„. ]. Introduces a subroutine. The USING and CHANGING additions define the subroutine’s...
6. FETCH : ABAP Keyword a day FETCH Basic form FETCH NEXT CURSOR c target. Effect Uses the cursor c to read the next line or lines from the dataset of a database table determined by OPEN...
7. DIVIDE : ABAP Keyword a day DIVIDE Basic form DIVIDE n1 BY n2. Effect Divides the contents of n1 by n2 and places the result in n1 . This is equivalent to: n1 = n1 /...
8. DESCRIBE : ABAP Keyword a day DESCRIBE Return attributes of a field - DESCRIBE FIELD f. Return attributes of an internal table - DESCRIBE TABLE itab. Determine distance between two fields - DESCRIBE DISTANCE BETWEEN f1...
9. DATA : ABAP Keyword a day DATA Variants1. DATA f.2. DATA f(len).3. DATA: BEGIN OF rec,…END OF rec.4. DATA: BEGIN OF itab OCCURS n,…END OF itab.5. DATA: BEGIN OF COMMON PART c,…END OF COMMON PART.EffectDefines global...
10. CONTINUE: ABAP Keyword a day CONTINUE Basic formCONTINUE.EffectWithin loop structures like * DO … ENDDO* WHILE … ENDWHILE* LOOP … ENDLOOP* SELECT … ENDSELECTCONTINUE terminates the current loop pass, returns the processing to the beginning...
11. CONCATENATE : ABAP Keyword a day CONCATENATE Basic form CONCATENATE f1 … fn INTO g. Addition … SEPARATED BY h Effect Places the fields f1 to fn after g . With the fields fi (1 <=...
12. COMPUTE: ABAP Keyword a day COMPUTEBasic formCOMPUTE n = arithexp.EffectEvaluates the arithmetic expression arithexp and places the result in the field n .Allows use of the four basic calculation types + , – , *...
13. CNT : ABAP Keyword a day CNT Basic form… CNT(h) …EffectCNT(h) is not a statement, but a field which is automatically created and filled by the system if f is a sub-field of an extract dataset...
14. CASE: ABAP Keyword a day CASE Basic formCASE f. Effect Case distinction.Depending on the current contents of a field, this statement executes one of several alternative processing branches. The field whose contents determine how the...
15. GET PARAMETER: ABAP Keyword a day GET PARAMETER Gets an SPA/GPA parameters. Syntax GET PARAMETER ID <pid> FIELD <field_name>. Writes the value of the SPA/GPA parameter <pid> from the user-specific SAP memory into the variable <f>....