diff options
Diffstat (limited to 'sql/table.h')
| -rw-r--r-- | sql/table.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/sql/table.h b/sql/table.h index 19256c67a52..98ec9f005ea 100644 --- a/sql/table.h +++ b/sql/table.h @@ -50,6 +50,7 @@ class ACL_internal_table_access; class Field; class Table_statistics; class TDC_element; +struct Name_resolution_context; /* Used to identify NESTED_JOIN structures within a join (applicable only to @@ -1828,6 +1829,7 @@ struct TABLE_LIST char *db, *alias, *table_name, *schema_table_name; char *option; /* Used by cache index */ Item *on_expr; /* Used with outer join */ + Name_resolution_context *on_context; /* For ON expressions */ Item *sj_on_expr; /* @@ -2555,9 +2557,31 @@ public: }; +#define JOIN_OP_NEST 1 +#define REBALANCED_NEST 2 + typedef struct st_nested_join { List<TABLE_LIST> join_list; /* list of elements in the nested join */ + /* + Currently the valid values for nest type are: + JOIN_OP_NEST - for nest created for JOIN operation used as an operand in + a join expression, contains 2 elements; + JOIN_OP_NEST | REBALANCED_NEST - nest created after tree re-balancing + in st_select_lex::add_cross_joined_table(), contains 1 element; + 0 - for all other nests. + Examples: + 1. SELECT * FROM t1 JOIN t2 LEFT JOIN t3 ON t2.a=t3.a; + Here the nest created for LEFT JOIN at first has nest_type==JOIN_OP_NEST. + After re-balancing in st_select_lex::add_cross_joined_table() this nest + has nest_type==JOIN_OP_NEST | REBALANCED_NEST. The nest for JOIN created + in st_select_lex::add_cross_joined_table() has nest_type== JOIN_OP_NEST. + 2. SELECT * FROM t1 JOIN (t2 LEFT JOIN t3 ON t2.a=t3.a) + Here the nest created for LEFT JOIN has nest_type==0, because it's not + an operand in a join expression. The nest created for JOIN has nest_type + set to JOIN_OP_NEST. + */ + uint nest_type; /* Bitmap of tables within this nested join (including those embedded within its children), including tables removed by table elimination. |