SAP ABAP Syntax For Delete From Internal Table Part Two

This is in continuation with DELETE DATA FROM INTERNAL TABLE PART ONE.

Variant 4

DELETE itab WHERE condition.

Additions

1. ... FROM idx1
2. ... TO idx2

Effect

Deletes all entries from internal table itab , which satisfies the condition condition .

The return code value is set as follows:

SY-SUBRC = 0 At least one entry was deleted.
SY_SUBRC = 4 None of the entries were deleted.

Addition 1

... FROM idx1

Effect

The line area to be investigated is restricted to the lines up to index idx1 . If the addition FROM idx1 is missing, a search is carried out from the beginning of the table.
The addition FROM must come before the WHERE condition.

Addition 2

... TO idx2

Effect

Restricts the line area to be investigated to the lines up to index idx2 . If the addition TO idx2 is missing, a search is carried out until the end of the table.
The addition TO must come before the WHERE condition.

Example

Delete all lines in a name table between lines 5 and 36, if the entry begins with one of the letters 'A' to 'C' :

DATA: BEGIN OF NAMETAB OCCURS 100,

        NAME(30) TYPE C,       END OF NAMETAB.

...

DELETE NAMETAB FROM 5 TO 36 WHERE NAME CA 'ABC'.

Variant 5

DELETE ADJACENT DUPLICATES FROM itab.

Additions

1. ... COMPARING f1 f2 ...
2. ... COMPARING ALL FIELDS

Effect

Deletes neighboring, duplicate entries from the internal table itab . If there are n duplicate entries, the first entry is retained and the other n - 1 entries are deleted.

Two lines are considered to be duplicated if their default keys match.

The return code value is set as follows:


SY-SUBRC = 0 At least one duplicate exists, at least one entry deleted.

SY_SUBRC = 4 No duplicates exist, no entry deleted.

Addition 1

... COMPARING f1 f2 ...

Effect

Two lines of the internal table itab are considered to be duplicates if the specified fields f1 , f2 , .... match.

Addition 2

... COMPARING ALL FIELDS

Effect

Two lines are considered to be duplicates if all fields of the table entries match.

Notes

The DELETE ADJACENT DUPLICATES statement is especially useful if the internal table itab is sorted by fields (whether in ascending or descending order) which were compared during duplicate determination. In this case, the deletion of neighbouring duplicates is the same as the deletion of all duplicates.
If a comparison criterion is only known at runtime, it can be specified dynamically as the content of a field name by using COMPARING ... (name) ... . If name is blank at runtime, the comparison criterion is ignored. If name contains an invalid component name, a runtime error occurs.
Comparison criteria - statistically or dynamically specified - can be further restriced by specifying the offset and/or length.

Note

Performance

Deleting a line from an internal table incurs index maintenance costs which depend on the index of the line to be deleted. The runtime depends on the line width of the table.

For example, deleting a line in the middle of an internal table with 200 entries requires about 10 msn (standardized microseconds).

Deleting a range of entries with " DELETE itab FROM idx1 TO idx2. " deleting a set of entries with " DELETE itab WHERE ... " only incur index maintenance costs once. Compared with a LOOP , which deletes line-by-line, this is much faster.
To delete neighboring, duplicate entries from an internal table, use the variant " DELETE ADJACENT DUPLICATES FROM itab. " instead of LOOP constructions.


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