Hi,
On 05/04/2016 12:52 AM, Alexander Barkov wrote:
Hi Sergei, If I run this query: SELECT 1 UNION SELECT 2 INTO OUTFILE 'test.txt'; It creates a file 'test.txt' with this content: 1 2 Looks fine so far. Now if I do "rm test.txt" and execute another query (with parentheses): (SELECT 1) UNION (SELECT 2 INTO OUTFILE 'test.txt'); it still puts the same two records from both UNION parts! This looks confusing, as parentheses a kind of assume that only the right UNION part is to be exported.
INTO @v1 is also confusing and is applied to the entire UNION, rather than a UNION part: (SELECT 1) UNION ALL (SELECT * FROM t1 LIMIT 1 INTO @v1); ERROR 1172 (42000): Result consisted of more than one row
Exporting only one UNION part is not supported, IIRC. So the above query should probably return a syntax error. But now there is a new trouble. There is no syntax like this: (SELECT ...) UNION (SELECT ...) INTO OUTFILE 'test.txt'; So instead of: (SELECT ...) UNION (SELECT ... INTO OUTFILE 'test.txt'); one will have to write this: SELECT * INTO OUTFILE 'test.txt' FROM ((SELECT ...) UNION (SELECT ...)) AS t1; The latter looks longer, but at least it's not confusing as the former.
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