Fix out-of-bound array access crash in select processing (#6594)

Fix test case.

pkg/s3select/select.go

@@ -370,8 +370,9 @@ func aggregationFunctions(counter int, filtrCount int, myAggVals []float64, colu
 			// If column names are provided as an index it'll use this if statement instead of the else/
 			var convAggFloat float64
 			if representsInt(storeReqCols[i]) {
-				myIndex, _ := strconv.Atoi(storeReqCols[i])
+				colIndex, _ := strconv.Atoi(storeReqCols[i])
-				convAggFloat, _ = strconv.ParseFloat(record[myIndex], 64)
+				// colIndex is 1-based
+				convAggFloat, _ = strconv.ParseFloat(record[colIndex-1], 64)
 
 			} else {
 				// case that the columns are in the form of named columns rather than indices.

pkg/s3select/select_test.go

@@ -331,7 +331,7 @@ func TestMyAggregationFunc(t *testing.T) {
 		{1, 1, []float64{10}, columnsMap, []string{"Col1"}, []string{"avg"}, []string{"1", "2"}, nil, 5.500},
 		{10, 5, []float64{0.000}, columnsMap, []string{"Col1"}, []string{"random"}, []string{"1", "2"}, ErrParseNonUnaryAgregateFunctionCall, 0},
 		{0, 5, []float64{0}, columnsMap, []string{"0"}, []string{"count"}, []string{"1", "2"}, nil, 1},
-		{10, 5, []float64{10}, columnsMap, []string{"1"}, []string{"min"}, []string{"1", "12"}, nil, 10},
+		{10, 5, []float64{10}, columnsMap, []string{"1"}, []string{"min"}, []string{"1", "12"}, nil, 1},
 	}
 	for _, table := range tables {
 		err := aggregationFunctions(table.counter, table.filtrCount, table.myAggVals, table.columnsMap, table.storeReqCols, table.storeFunctions, table.record)