Merge pull request #2298 from Mytherin/issue2294

Fix #2294: In CSV reader correctly generate column names with many columns
duckdb · Sep 20, 2021 · 0e6969f · 0e6969f
2 parents 7dd852e + a9cadc0
commit 0e6969f
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Showing 3 changed files with 14 additions and 1 deletion.
diff --git a/src/execution/operator/persistent/buffered_csv_reader.cpp b/src/execution/operator/persistent/buffered_csv_reader.cpp
@@ -176,7 +176,7 @@ unique_ptr<FileHandle> BufferedCSVReader::OpenCSV(const BufferedCSVReaderOptions
 static string GenerateColumnName(const idx_t total_cols, const idx_t col_number, const string &prefix = "column") {
 	int max_digits = NumericHelper::UnsignedLength(total_cols - 1);
 	int digits = NumericHelper::UnsignedLength(col_number);
-	string leading_zeros = string("0", max_digits - digits);
+	string leading_zeros = string(max_digits - digits, '0');
 	string value = to_string(col_number);
 	return string(prefix + leading_zeros + value);
 }

diff --git a/test/sql/copy/csv/data/manycolumns.csv b/test/sql/copy/csv/data/manycolumns.csv
@@ -0,0 +1 @@
+1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101
diff --git a/test/sql/copy/csv/test_many_columns.test b/test/sql/copy/csv/test_many_columns.test
@@ -0,0 +1,12 @@
+# name: test/sql/copy/csv/test_many_columns.test
+# description: Test read CSV function with many (>100) auto-generated columns
+# group: [csv]
+
+statement ok
+PRAGMA enable_verification
+
+statement ok
+CREATE TABLE t AS SELECT * FROM read_csv_auto('test/sql/copy/csv/data/manycolumns.csv');
+
+statement ok
+PRAGMA SHOW('t');