Solution : https://service.sap.com/sap/support/notes/1640917 (SAP Service marketplace login required)
Key words : 
terms trex_ext_merge_delta_index trex_dbs_merge_delta_index history reason, sql syntax error occurs, function module trex_ext_merge_delta_index, sql syntax error, prerequisites typing error, import parameter i_history=1, solution apply patch, source code correction, incorrect syntax, problem occurs
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