When running MD01, purchase requisition was not created to a certain material, but when using MD02, purchase requisition was created.
 
Answer:
 
MD01 requires a planning file entry, MD02 does not. Check/create appropriate entries in MD20. For all materials in background use MDAB. Might also have to fix inconsistencies using MDRE.
 
Depending on how your master data is being maintained, you may not automatically get a planning file entry when a material is made relevant for planning. As a backstop measure, many companies rebuild the planning files regularly just prior to the MRP runs, using the batch program noted earlier.
 
 
Checklist when purchase requisition not created:
 
- Check whether you have maintained the purchasing view for that raw material or not.
 
- Check if already there is stock of the raw material maintained in the system. If the available stock is sufficient for the order quantity, then the system will not generate purchase requisition. Run MD04 / MD05 and check order tree for the material for which you are doing the MRP run. System will show if there is stock available.
 
- Check whether the Material is defined for "F" - External Procurement in MRP2 view of the material master.
 
- Check whether the material type used for the material is enabled for "External Purchase orders". Transaction 'OMS2'.
 
- Check purchase requisition number range is not exhausted.  Tcode 'OMH7'.
 

Notes:
 
If you have updated MD20 you cannot revert back the changes made.
 
Reverting this entry is not standard SAP functionality. In the most common business scenarios, if one wishes to be able to plan a material using MRP, they also need to have a planning file entry. SAP will normally create this entry automatically under most standard conditions that require it. Certain uncommon scenarios will leave a material/plant in a condition where planning is required, but SAP has not created the appropriate planning file entry. For these instances, SAP provides the transactions I mentioned previously.
 
Archiving (physically deleting a material from the database and copying it to long-term storage) will remove planning file entries. Changing a material to non-planable (ND) will remove the entry. I can't think of any other standard MRP process that will remove a planning file entry.
 
The usual business requirement is, "how can I ensure that all planable materials have the appropriate planning file entry". 
 
 
What code to display all Purchase Requisition generated by MRP LIST?
 
You need to use ME5A report with dynamic selection. In dynamic selection (it will appear next to variant button) you need to choose creation indicator. Give creation indicator as "B" which material requirement planning and execute the report.

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