PLPH is a standard SAP Table which is used to store CAPP: Sub-operations data in SAP systems, such as SAP R/3, S/4HANA, depending on the version and release level.
The PLPH table consists of various fields, each holding specific information or linking keys about CAPP: Sub-operations data available in SAP. These include PLNTY (Task List Type), PLNNR (Key for Task List Group), PLNKN (Number of the task list node), PLNPH (Internal Sub-Calculation Number)... 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. .