我试图简单地把12张桌子全部合并。 所有表格加在一起,有115行。 然而,如果我处理下面的提问,那么我会利用解释以及在我的餐桌上作一个入场。 用于记录-频率-非使用-指数的标识:
Rows_sent: 115 Rows_examined: 1008
我稍感想一下的是,当我所必须做的一切只是一起加入(福利、工会)时,我的sql正在研究1008个牢房。 任何背心或指点都将受到高度赞赏。
这里要问:
(SELECT id, var_lng_1, 0 as tbl_col FROM tbl1 )
UNION ALL
(SELECT id, var_lng_1, 1 as tbl_col FROM tbl2 )
UNION ALL
(SELECT id, var_lng_1, 2 as tbl_col FROM tbl3 )
UNION ALL
(SELECT id, var_lng_1, 3 as tbl_col FROM tbl4 )
UNION ALL
(SELECT id, var_lng_1, 4 as tbl_col FROM tbl5 )
UNION ALL
(SELECT id, var_lng_1, 5 as tbl_col FROM tbl6 )
UNION ALL
(SELECT id, var_lng_1, 6 as tbl_col FROM tbl7 )
UNION ALL
(SELECT id, var_lng_1, 7 as tbl_col FROM tbl8 )
UNION ALL
(SELECT id, var_lng_1, 8 as tbl_col FROM tbl9 )
UNION ALL
(SELECT id, var_lng_1, 9 as tbl_col FROM tbl10 )
UNION ALL
(SELECT id, var_lng_1, 10 as tbl_col FROM tbl11 )
UNION ALL
(SELECT id, var_lng_1, 11 as tbl_col FROM tbl12 );
赞赏任何投入
PS: (如果情况会有所改变),所有补贴都是初级、中级、直线(3)、汽车-水泥一栏。 我也尝试了同样的询问(即从......选择补贴,但没有区别):
全面解释产出:
[id] => 1
[select_type] => PRIMARY
[table] => tbl1
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 7
[Extra] =>
[id] => 2
[select_type] => UNION
[table] => tbl2
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 18
[Extra] =>
[id] => 3
[select_type] => UNION
[table] => tbl3
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 8
[Extra] =>
[id] => 4
[select_type] => UNION
[table] => tbl4
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 10
[Extra] =>
[id] => 5
[select_type] => UNION
[table] => tbl5
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 11
[Extra] =>
[id] => 6
[select_type] => UNION
[table] => tbl6
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 14
[Extra] =>
[id] => 7
[select_type] => UNION
[table] => tbl7
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 10
[Extra] =>
[id] => 8
[select_type] => UNION
[table] => tbl8
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 6
[Extra] =>
[id] => 9
[select_type] => UNION
[table] => tbl9
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 3
[Extra] =>
[id] => 10
[select_type] => UNION
[table] => tbl10
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 2
[Extra] =>
[id] => 11
[select_type] => UNION
[table] => tbl11
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 6
[Extra] =>
[id] => 12
[select_type] => UNION
[table] => tbl12
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] => 20
[Extra] =>
[id] =>
[select_type] => UNION RESULT
[table] => <union1,2,3,4,5,6,7,8,9,10,11,12>
[type] => ALL
[possible_keys] =>
[key] =>
[key_len] =>
[ref] =>
[rows] =>
[Extra] =>