ABAP Keyword Documentation → ABAP - Reference → Processing Internal Data → Internal Tables → Processing Statements for Internal Tables
READ TABLE itab
Other versions: 7.31 | 7.40 | 7.54
Syntax
READ TABLE itab { table_key
| free_key
|
index } result.
Effect
This statement reads a row from the internal table itab. itab is a
functional operand position.
The row must be specified by naming values for either
table_key for a table key, a free condition
free_key, or an index index. The latter is possible only for
index tables and when using a
sorted
secondary key.
The output response result determines how and to where the row contents are read.
If the row to be read is not specified uniquely, the first suitable row is read. In the case of index tables, this row has the lowest row number of all suitable rows in the table index used.
If the internal table is specified as the return value or result of a functional method, a constructor expression, or a table expression, the value is only available when the statement is executed. Afterwards, it is no longer possible to access the internal table.
System Fields
The statement READ TABLE sets the values for the system fields sy-subrc and sy-tabix.
| sy-subrc | Meaning |
|---|---|
| 0 | Row is found. sy-tabix is set to the row number of the entry in the primary or secondary table index used. If ahash key is used, it is set to 0. |
| 2 | Like sy-subrc equals 0. Distinguishes cases that use the addition COMPARING in result. |
| 4 | The row was not found. If the entry was determined using a binary search, sy-tabixis set to the table index of the entry before which it would be inserted using INSERT ... INDEX ..., to preserve the sort order. This is the case if, whensorted keys are used, theaddition table_key or free_key was specified alongside the full table key or if the additionBINARY SEARCH was specified explicitly. Otherwise, sy-tabix is undefined (-1). |
| 8 | Like sy-subrc equals 4. If the entry was determined using a binary search,and the end of the table was reached, then sy-tabix is set to the number of rows + 1. |
The system fields sy-tfill and sy-tleng are also filled.
Notes
- There is no implicit selection of a suitable key or index. The used table key or table index is always specified uniquely. The syntax check issues a warning if there is a suitable secondary table key but this table key is not used. This warning should be removed through using the key. However, in exceptional cases, it can be bypassed using a pragma.
-
As an alternative to the statement
READ TABLE, table expressions can be used to allow reads to be performed on individual table rows at operand positions. -
If multiple rows of an internal table are to be read, the statement
LOOP generally displays better performance than using the statement
READ TABLEin a loop.
Exceptions
Non-Catchable Exceptions
-
Cause: When reading a table with
READ ... WITH [TABLE] KEY, overlapping or duplicate key specifications were used.
Runtime Error:DYN_KEY_DUPLICATE -
Cause: When reading a table of the type
SORTED, the specified key fields have to be an initial part of the table key whenBINARY SEARCHis specified.
Runtime Error:ITAB_ILLEGAL_BINARY_SEARCH -
Cause: No key specified.
Runtime Error:ITAB_KEY_COMPONENT_MISSING -
Cause: Invalid key specified when accessing a key table.
Runtime Error:ITAB_KEY_ILLEGAL_COMPONENT -
Cause: Invalid key specified implicitly in the Unicode context.
Runtime Error:READ_ITAB_UC_KEY_ERROR -
Cause: Invalid incompatible work area specified.
Runtime Error:OBJECTS_WA_NOT_COMPATIBLE -
Cause: Memory area violated when
TABLESparameter accessed
Runtime Error:ITAB_STRUC_ACCESS_VIOLATION