Archived: Fetching Non-ASCII Text from MySQL 5

∟Archived: Fetching Non-ASCII Text from MySQL 5

This section describes how to set character_set_results properly to retrieve non-ASCII character strings from MySQL 5 server.

Based on the analysis provided in the previous section, I revised my PHP script to set character_set_results to utf8. Hope this will allow me to fetch non-ASCII characters correctly from the String_UTF8 column on MySQL 5:

<?php 
#- MySQL-Fetch-Non-ASCII-UTF8.php
#- Copyright (c) 2005 HerongYang.com. All Rights Reserved.
#
  $con = mysql_connect("localhost", "Herong", "TopSecret");
  $ok = mysql_select_db("HerongDB", $con);
  $test_name = "Non-ASCII Test";

# Set character_set_results
  $sql = "SET character_set_results=utf8";
  mysql_query($sql, $con);

# Show character set encoding variables
  $sql = "SHOW VARIABLES LIKE 'character_set_%'";
  $res = mysql_query($sql, $con);
  while ($row = mysql_fetch_array($res)) {
    print($row['Variable_name']." = ".$row['Value']."\n");
  }  
  mysql_free_result($res);

# Delete the record
  $sql = "DELETE FROM Comment_Mixed WHERE Test_Name ='$test_name'";
  mysql_query($sql, $con);
  print("\nNumber of rows deleted: ".mysql_affected_rows()."\n");

# Build the SQL INSERT statement
  $sql = <<<END_OF_MESSAGE
INSERT INTO Comment_Mixed (Test_name, String_ASCII, 
    String_Latin1, String_UTF8, String_GBK, String_Big5)
  VALUES ('$test_name', 'Television', 
    X'54E96CE9766973696E6F', 
    X'E794B5E8A786E69CBA2FE99BBBE8A696E6A99F', 
    X'B5E7CAD3BBFA', 
    X'B971B5F8BEF7');
END_OF_MESSAGE;

# Run the SQL statement
  if (mysql_query($sql, $con)) {
    print("\nNumber of rows inserted: ".mysql_affected_rows()."\n");
  } else {
    print("SQL statement failed.\n");
    print(mysql_errno($con).": ".mysql_error($con)."\n"); 
  }

# Get the recode back
  $sql = "SELECT * FROM Comment_Mixed"
    . " WHERE Test_Name = '$test_name'";
  $res = mysql_query($sql, $con);
  if ($row = mysql_fetch_array($res)) {
    print("\nTest Name = ".$row['Test_Name']."\n");
    print("   String_ASCII: 0x".bin2hex($row['String_ASCII'])."\n");
    print("   String_Latin1: 0x".bin2hex($row['String_Latin1'])."\n");
    print("   String_UTF8: 0x".bin2hex($row['String_UTF8'])."\n");
    print("   String_GBK: 0x".bin2hex($row['String_GBK'])."\n");
    print("   String_Big5: 0x".bin2hex($row['String_Big5'])."\n");
  }  
  mysql_free_result($res);

  mysql_close($con); 
?>

The output confirms that character_set_results=utf8 helped to stop the wrong conversion on non-ASCII characters fetched from the String_UTF8 column on MySQL 5:

C:\herong> \local\php\php MySQL-Fetch-Non-ASCII-UTF8.php
character_set_client = latin1
character_set_connection = latin1
character_set_database = latin1
character_set_filesystem = binary
character_set_results = utf8
character_set_server = latin1
character_set_system = utf8
character_sets_dir = \local\mysql\share\charsets\

Number of rows deleted: 1

Number of rows inserted: 1

Test Name = Non-ASCII Test
   String_ASCII: 0x54656c65766973696f6e
   String_Latin1: 0x54c3a96cc3a9766973696e6f
   String_UTF8: 0xe794b5e8a786e69cba2fe99bbbe8a696e6a99f
   String_GBK: 0xe794b5e8a786e69cba
   String_Big5: 0xe99bbbe8a696e6a99f

However, other encoding conversions were performed on other non-ASCII columns:

ASCII characters fetched from String_ASCII column were converted to UTF8. No problem.
Latin1 characters fetched from String_Latin1 column were converted to UTF8. MySQL did a real conversion here. Notice that the French character 0xE9 were converted to 0xC3A9.
UTF-8 characters fetched from String_UTF8 column were converted to UTF8. Perfect match. No conversion.
GBK characters fetched from String_GBK column were converted to UTF8. MySQL did a real conversion and did it correctly. Notice that the GBK string 0xB5E7CAD3BBFA was converted to 0xE794B5E8A786E69CBA, which match the UTF-8 string I entered for the String_UTF8 column.
Big5 characters fetched from String_Big5 column were converted to UTF8. MySQL did a real conversion and did it correctly. Notice that the Big5 string 0xB971B5F8BEF7 was converted to 0xE99BBBE8A696E6A99F, which match the UTF-8 string I entered for the String_UTF8 column.

My conclusion is that:

If you are working with a single character set encoding, set character_set_results to that encoding.
If you are working with multiple character set encodings, set character_set_results to the UTF-8, which is bigger than other encodings. MySQL will convert fetched text from the encoding of the original column to UTF-8 correctly for you.