COND_SELFIELD is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Structure for Selection Fields" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_COND_SELFIELD TYPE COND_SELFIELD.
The COND_SELFIELD table consists of various fields, each holding specific information or linking keys about Structure for Selection Fields data available in SAP. These include IS_MANDATORY (Required field flag), SIGN (Include/Exclude Criterion), GROUPFLAG (Group Field for Condition Fields)... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .