CREATE TABLE some_table ( field1 int(11) NOT NULL AUTO_INCREMENT, field2 varchar(10) NOT NULL, field3 varchar(10) NOT NULL, PRIMARY KEY (`field1`));INSERT INTO `some_table` (field1, field2, field3) VALUES(1, 'text one', 'foo'),(2, 'text two', 'bar'),(3, 'text three', 'data'),(4, 'text four', 'magic');
这个查询有点奇怪，但是不需要另一个查询来初始化变量。并且可以将其嵌入更复杂的查询中。它返回所有用分号分隔的“ field2”。
SELECt resultFROM (SELECt @result := '', (SELECT result FROM (SELECt @result := CONCAT_Ws(';', @result, field2) AS result, LENGTH(@result) AS blength FROM some_table ORDER BY blength DESC LIMIT 1) AS sub1) AS result) AS sub2;
