Details
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Task
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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None
Description
The "table_ref" rule allows non-parenthesized SELECT query.
table_ref is used in derived_table_list and join_table.
Non-parenthesized SELECT query is OK in derived_table_list, which is used (among other things) to handle derived tables in FROM clause:
SELECT * FROM (SELECT * FROM t1);
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But when table_ref is used in join_table, non-parenthesized SELECT should not be allowed:
join_table:
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table_ref normal_join table_ref
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| table_ref normal_join table_ref ON ...
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| table_ref normal_join table_ref USING ...
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| table_ref NATURAL inner_join table_factor
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| table_ref LEFT opt_outer JOIN_SYM table_ref ON ...
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| table_ref LEFT opt_outer JOIN_SYM table_factor USING
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| table_ref NATURAL LEFT opt_outer JOIN_SYM table_factor
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| table_ref RIGHT opt_outer JOIN_SYM table_ref ON ...
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| table_ref RIGHT opt_outer JOIN_SYM table_factor USING ...
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| table_ref NATURAL RIGHT opt_outer JOIN_SYM table_factor
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;
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Examples of bad queries:
SELECT * FROM (SELECT 1 NATURAL JOIN t2); -- SELECT 1 on the left side of JOIN is incorrect |
SELECT * FROM t1 NATURAL JOIN SELECT 1; -- SELECT on the right side of JOIN is incorrect |
Currently bad queries are caught by extra code:
{
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MYSQL_YYABORT_UNLESS($1 && ($$=$4));
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$4->straight=$3;
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add_join_natural($1,$4,NULL,Select);
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}
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if (!sel->embedding || sel->end_nested_join(lex->thd)) |
{
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/* we are not in parentheses */ |
my_parse_error(thd, ER_SYNTAX_ERROR);
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MYSQL_YYABORT;
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}
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Under terms of this task we'll disallow such queries syntactically, by moving non-parenthesized SELECT from table_ref to derived_table_list.
Unfortunately, it's not possible to remove the extra code at this stage, because it's used for some other purposes as well.
Attachments
Issue Links
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- Closed
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