Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.2.16, 10.2(EOL), 10.3(EOL)
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None
Description
Let's say that we have the following table:
CREATE TABLE json_test (
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json_col TEXT
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) DEFAULT CHARSET=latin1;
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|
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INSERT INTO json_test VALUES ('{"key1":"Sí"}');
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We can get the value of key1 by executing the following:
SELECT JSON_VALUE(json_col, '$.key1') FROM json_test;
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And this works fine:
MariaDB [db1]> SELECT JSON_VALUE(json_col, '$.key1') FROM json_test;
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+--------------------------------+
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| JSON_VALUE(json_col, '$.key1') |
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+--------------------------------+
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| Sí |
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+--------------------------------+
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1 row in set (0.00 sec)
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But if we combine this with string functions, then the character set gets messed up. For example, run the following queries instead:
SELECT REPLACE(JSON_VALUE(json_col, '$.key1'), 'null', '') FROM json_test;
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SELECT CONCAT(json_value(json_col, '$.key1'), 'a') FROM json_test;
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And we get something unexpected:
MariaDB [db1]> SELECT REPLACE(JSON_VALUE(json_col, '$.key1'), 'null', '') FROM json_test;
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+-----------------------------------------------------+
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| REPLACE(JSON_VALUE(json_col, '$.key1'), 'null', '') |
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+-----------------------------------------------------+
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| SÃ |
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+-----------------------------------------------------+
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1 row in set (0.00 sec)
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|
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MariaDB [db1]> SELECT CONCAT(json_value(json_col, '$.key1'), 'a') FROM json_test;
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+---------------------------------------------+
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| CONCAT(json_value(json_col, '$.key1'), 'a') |
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+---------------------------------------------+
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| SÃa |
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+---------------------------------------------+
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1 row in set (0.00 sec)
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We can workaround this problem by explicitly converting the JSON_VALUE return value to a given character set:
MariaDB [db1]> SELECT REPLACE(CONVERT(JSON_VALUE(json_col, '$.key1') USING utf8), 'null', '') FROM json_test;
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+-------------------------------------------------------------------------+
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| REPLACE(CONVERT(JSON_VALUE(json_col, '$.key1') USING utf8), 'null', '') |
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+-------------------------------------------------------------------------+
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| Sí |
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+-------------------------------------------------------------------------+
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1 row in set (0.00 sec)
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