Explanation
The ABAP SQL clause that allows the use of inline declarations is the INTO clause. The INTO clause is used to specify the target variable or field symbol where the result of the SQL query is stored. The INTO clause can use inline declarations to declare the target variable or field symbol at the same position where it is used, without using a separate DATA or FIELD-SYMBOLS statement. The inline declaration is performed using the DATA or @DATA operators in the declaration expression12. For example:
The following code snippet uses the INTO clause with an inline declaration to declare a local variable itab and store the result of the SELECT query into it:
SELECT * FROM scarr INTO TABLE @DATA (itab).
The following code snippet uses the INTO clause with an inline declaration to declare a field symbol
<fs> and store the result of the SELECT query into it:
SELECT SINGLE * FROM scarr INTO @<fs>.
You cannot do any of the following:
FROM: The FROM clause is used to specify the data source of the SQL query, such as a table, a view, or a join expression. The FROM clause does not allow the use of inline declarations12.
INTO CORRESPONDING FIELDS OF: The INTO CORRESPONDING FIELDS OF clause is used to specify the target structure or table where the result of the SQL query is stored. The INTO CORRESPONDING FIELDS OF clause does not allow the use of inline declarations. The target structure or table must be declared beforehand using a DATA or FIELD-SYMBOLS statement12.
FIELDS: The FIELDS clause is used to specify the columns or expressions that are selected from the data source of the SQL query. The FIELDS clause does not allow the use of inline declarations. The FIELDS clause must be followed by an INTO clause that specifies the target variable or field symbol where the result is stored12.
References: 1: SELECT - ABAP Keyword Documentation - SAP Online Help 2: Inline Declarations - ABAP Keyword Documentation - SAP Online Help