Reading data from several tables

We have several possibilities for reading data from several tables in SQL and merging that data in one internal table. I will present three possibilities for getting the data from several tables into one internal table. Here, we can use FOR ALL ENTRIES, SELECT...ENDSELECT, and JOIN. As the mechanism and principle of the FOR ALL ENTRIESoperation has been discussed previously, I have only shown how to get data from several tables.

We need to split a query into two SELECT statements. However, first of all, I will prepare the structure and table when we have fields from two tables—sflight and spfli:

TYPES:
BEGIN OF s_for_all_entries,
     mandt     TYPE mandt,
     carrid    TYPE s_carr_id,
     connid    TYPE s_conn_id,
     fldate    TYPE s_date,
     countryfr TYPE land1,
     cityfrom  TYPE s_from_cit,
     airpfrom  TYPE s_fromairp,
     countryto TYPE land1,
     cityto    TYPE s_to_city,
     airpto    TYPE s_toairp,
END OF s_for_all_entries.

DATA: gt_for_all_enties...