Fixed bug #29442.

The SELECT INTO OUTFILE FIELDS ENCLOSED BY digit or minus sign,
followed by the same LOAD DATA INFILE statement, used wrond encoding
of non-string fields contained the enclosed character in their text
representation.

Example:
  SELECT 15, 9 INTO OUTFILE 'text' FIELDS ENCLOSED BY '5';

Old encoded result in the text file:
  5155 595
         ^ was decoded as the 1st enclosing character of the 2nd field;
        ^ was skipped as garbage;
  ^    ^ was decoded as a pair of englosing characters of the 1st field;
      ^   was decoded as traling space of the first field;
    ^^ was decoded as a doubled enclosed character.

New encoded result in the text file:
  51\55 595
  ^   ^ pair of enclosing characters of the 1st field;
    ^^ escaped enclosed character.

mysql-test/r/loaddata.result

@@ -238,3 +238,17 @@ f1
 1
 2
 drop table t1,t2;
+CREATE TABLE t1 (c1 INT, c2 TIMESTAMP, c3 REAL, c4 DOUBLE);
+INSERT INTO t1 (c1, c2, c3, c4) VALUES (10, '1970-02-01 01:02:03', 1.1E-100, 1.1E+100);
+SELECT * FROM t1;
+c1	c2	c3	c4
+10	1970-02-01 01:02:03	1.1e-100	1.1e+100
+SELECT * INTO OUTFILE 'MYSQLTEST_VARDIR/tmp/t1' FIELDS ENCLOSED BY '-' FROM t1;
+-10-	-1970\-02\-01 01:02:03-	-1.1e\-100-	-1.1e+100-
+EOF
+TRUNCATE t1;
+LOAD DATA INFILE 'MYSQLTEST_VARDIR/tmp/t1' INTO TABLE t1 FIELDS ENCLOSED BY '-';
+SELECT * FROM t1;
+c1	c2	c3	c4
+10	1970-02-01 01:02:03	1.1e-100	1.1e+100
+DROP TABLE t1;

mysql-test/t/loaddata.test

@@ -213,4 +213,29 @@ select f1 from t1 where f2 <> '0000-00-00 00:00:00' order by f1;
 --exec rm $MYSQLTEST_VARDIR/tmp/t2
 drop table t1,t2;
 
+#
+# Bug#29442: SELECT INTO OUTFILE FIELDS ENCLOSED BY digit, minus sign etc
+#            corrupts non-string fields containing this character.
+#
+
+CREATE TABLE t1 (c1 INT, c2 TIMESTAMP, c3 REAL, c4 DOUBLE);
+
+INSERT INTO t1 (c1, c2, c3, c4) VALUES (10, '1970-02-01 01:02:03', 1.1E-100, 1.1E+100);
+SELECT * FROM t1;
+
+--exec rm -f $MYSQLTEST_VARDIR/tmp/t1
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+eval SELECT * INTO OUTFILE '$MYSQLTEST_VARDIR/tmp/t1' FIELDS ENCLOSED BY '-' FROM t1;
+--exec cat $MYSQLTEST_VARDIR/tmp/t1
+--exec echo EOF
+
+TRUNCATE t1;
+
+--replace_result $MYSQLTEST_VARDIR MYSQLTEST_VARDIR
+eval LOAD DATA INFILE '$MYSQLTEST_VARDIR/tmp/t1' INTO TABLE t1 FIELDS ENCLOSED BY '-';
+SELECT * FROM t1;
+
+--exec rm $MYSQLTEST_VARDIR/tmp/t1
+DROP TABLE t1;
+
 # End of 5.0 tests

sql/sql_class.cc

@@ -1210,6 +1210,7 @@ select_export::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
 		   field_term_length ? (*exchange->field_term)[0] : INT_MAX);
   escape_char=	(exchange->escaped->length() ? (*exchange->escaped)[0] : -1);
   is_ambiguous_field_sep= test(strchr(ESCAPE_CHARS, field_sep_char));
+  is_unsafe_field_sep= test(strchr(NUMERIC_CHARS, field_sep_char));
   line_sep_char= (exchange->line_term->length() ?
 		  (*exchange->line_term)[0] : INT_MAX);
   if (!field_term_length)
@@ -1284,7 +1285,8 @@ bool select_export::send_data(List<Item> &items)
 	used_length=min(res->length(),item->max_length);
       else
 	used_length=res->length();
-      if (result_type == STRING_RESULT && escape_char != -1)
+      if ((result_type == STRING_RESULT || is_unsafe_field_sep) &&
+           escape_char != -1)
       {
         char *pos, *start, *end;
         CHARSET_INFO *res_charset= res->charset();

sql/sql_class.h

@@ -1929,6 +1929,12 @@ class select_to_file :public select_result_interceptor {
 #define ESCAPE_CHARS "ntrb0ZN" // keep synchronous with READ_INFO::unescape
 
 
+/*
+ List of all possible characters of a numeric value text representation.
+*/
+#define NUMERIC_CHARS ".0123456789e+-"
+
+
 class select_export :public select_to_file {
   uint field_term_length;
   int field_sep_char,escape_char,line_sep_char;
@@ -1938,6 +1944,12 @@ class select_export :public select_to_file {
     (see the READ_INFO::unescape method and the ESCAPE_CHARS constant value).
   */
   bool is_ambiguous_field_sep;
+  /*
+    The is_unsafe_field_sep field is true if a value of the field_sep_char
+    field is one of the '0'..'9', '+', '-', '.' and 'e' characters
+    (see the NUMERIC_CHARS constant value).
+  */
+  bool is_unsafe_field_sep;
   bool fixed_row_size;
 public:
   select_export(sql_exchange *ex) :select_to_file(ex) {}