SELECT optimization for performance improvement

Hi guys,

I have tried to optimize a program coding for the sake of performance improvement. The original coding was as follow

I have united SELECT statements in INNER JOIN as following

Unfortunately it didn’t bring any improvements. In opposite, it costs now more time with one SELECT. I am confused. Please advise what I did wrong. Below are screen shots from trace list (trx. ST05) for the coding BEFORE and AFTER.

For the information: 3 DB tables are involved (CRM system): ADRC, BUT020 and CRMD_ORDER_INDEX.

If I understood the trace list correctly, the system uses primary index for tables ADRC (key field ADDRNUMBER) and BUT020 (key field PARTNER + ADDRNUMBER). For the table CRMD_ORDER_INDEX the secondary index is used (screen shot is below)

Thanks in advance

Best regards

Andrej