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A draft comment for mysql_select. Feel free to moderate and improve.

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konstantin@mysql.com 2005-05-18 19:35:20 +04:00
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44
sql/sql_select.cc
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@ -1932,6 +1932,50 @@ Cursor::~Cursor()
/*********************************************************************/
/*
An entry point to single-unit select (a select without UNION).
SYNOPSIS
mysql_select()
thd thread handler
rref_pointer_array a reference to ref_pointer_array of
the top-level select_lex for this query
tables list of all tables used in this query.
The tables have been pre-opened.
wild_num number of wildcards used in the top level
select of this query.
For example statement
SELECT *, t1.*, catalog.t2.* FROM t0, t1, t2;
has 3 wildcards.
fields list of items in SELECT list of the top-level
select
e.g. SELECT a, b, c FROM t1 will have Item_field
for a, b and c in this list.
conds top level item of an expression representing
WHERE clause of the top level select
og_num total number of ORDER BY and GROUP BY clauses
arguments
order linked list of ORDER BY agruments
group linked list of GROUP BY arguments
having top level item of HAVING expression
proc_param list of PROCEDUREs
select_options select options (BIG_RESULT, etc)
result an instance of result set handling class.
This object is responsible for send result
set rows to the client or inserting them
into a table.
select_lex the only SELECT_LEX of this query
unit top-level UNIT of this query
UNIT is an artificial object created by the parser
for every SELECT clause.
e.g. SELECT * FROM t1 WHERE a1 IN (SELECT * FROM t2)
has 2 unions.
RETURN VALUE
FALSE success
TRUE an error
*/
bool
mysql_select(THD *thd, Item ***rref_pointer_array,