public static string GetMergeQuery()

in src/SqlAsyncCollector.cs [528:557]
28 lines of code
3 McCabe index (conditional complexity)

            public static string GetMergeQuery(IList<PrimaryKey> primaryKeys, SqlObject table, IEnumerable<string> bracketedColumnNamesFromItem)
            {
                IList<string> bracketedPrimaryKeys = primaryKeys.Select(p => p.Name.AsBracketQuotedString()).ToList();
                // Generate the ON part of the merge query (compares new data against existing data)
                var primaryKeyMatchingQuery = new StringBuilder($"ExistingData.{bracketedPrimaryKeys[0]} = NewData.{bracketedPrimaryKeys[0]}");
                foreach (string primaryKey in bracketedPrimaryKeys.Skip(1))
                {
                    primaryKeyMatchingQuery.Append($" AND ExistingData.{primaryKey} = NewData.{primaryKey}");
                }

                // Generate the UPDATE part of the merge query (all columns that should be updated)
                var columnMatchingQueryBuilder = new StringBuilder();
                foreach (string column in bracketedColumnNamesFromItem)
                {
                    columnMatchingQueryBuilder.Append($" ExistingData.{column} = NewData.{column},");
                }

                string columnMatchingQuery = columnMatchingQueryBuilder.ToString().TrimEnd(',');
                return $@"
                    MERGE INTO {table.BracketQuotedFullName} WITH (HOLDLOCK)
                        AS ExistingData
                    USING {CteName}
                        AS NewData
                    ON
                        {primaryKeyMatchingQuery}
                    WHEN MATCHED THEN
                        UPDATE SET {columnMatchingQuery}
                    WHEN NOT MATCHED THEN
                        INSERT ({string.Join(",", bracketedColumnNamesFromItem)}) VALUES ({string.Join(",", bracketedColumnNamesFromItem)})";
            }