Query time 0.00055
JSON explain
{
"query_block": {
"select_id": 1,
"cost_info": {
"query_cost": "115.21"
},
"grouping_operation": {
"using_filesort": false,
"nested_loop": [
{
"table": {
"table_name": "q_discussion",
"access_type": "range",
"possible_keys": [
"object_id"
],
"key": "object_id",
"used_key_parts": [
"object_id",
"object_type"
],
"key_length": "6",
"rows_examined_per_scan": 16,
"rows_produced_per_join": 16,
"filtered": "100.00",
"index_condition": "((`portal`.`q_discussion`.`object_id` in (32877,32878,30350,14312,14348,15787,16532,16533,16536,16541,16542,16543,16553,16554,16555,16556)) and (`portal`.`q_discussion`.`object_type` = 'P'))",
"cost_info": {
"read_cost": "35.21",
"eval_cost": "3.20",
"prefix_cost": "38.41",
"data_read_per_join": "256"
},
"used_columns": [
"thread_id",
"object_id",
"object_type",
"type"
]
}
},
{
"table": {
"table_name": "q_discussion_posts",
"access_type": "ref",
"possible_keys": [
"thread_id",
"thread_id_2"
],
"key": "thread_id",
"used_key_parts": [
"thread_id"
],
"key_length": "3",
"ref": [
"portal.q_discussion.thread_id"
],
"rows_examined_per_scan": 2,
"rows_produced_per_join": 32,
"filtered": "100.00",
"cost_info": {
"read_cost": "32.00",
"eval_cost": "6.40",
"prefix_cost": "76.81",
"data_read_per_join": "14K"
},
"used_columns": [
"post_id",
"thread_id",
"status"
],
"attached_condition": "<if>(is_not_null_compl(q_discussion_posts), (`portal`.`q_discussion_posts`.`status` = 'A'), true)"
}
},
{
"table": {
"table_name": "q_discussion_rating",
"access_type": "eq_ref",
"possible_keys": [
"PRIMARY",
"thread_id"
],
"key": "PRIMARY",
"used_key_parts": [
"post_id"
],
"key_length": "3",
"ref": [
"portal.q_discussion_posts.post_id"
],
"rows_examined_per_scan": 1,
"rows_produced_per_join": 32,
"filtered": "100.00",
"cost_info": {
"read_cost": "32.00",
"eval_cost": "6.40",
"prefix_cost": "115.21",
"data_read_per_join": "512"
},
"used_columns": [
"rating_value",
"post_id",
"thread_id"
],
"attached_condition": "<if>(is_not_null_compl(q_discussion_rating), ((`portal`.`q_discussion_rating`.`thread_id` = `portal`.`q_discussion`.`thread_id`) and (`portal`.`q_discussion_rating`.`rating_value` <> 0)), true)"
}
}
]
}
}
}
Result
product_id |
average_rating |
discussion_type |
discussion_thread_id |
14312 |
|
B |
12277 |
14348 |
|
B |
12294 |
15787 |
|
B |
9620 |
16532 |
|
B |
8293 |
16533 |
|
B |
8296 |
16536 |
|
B |
8304 |
16541 |
|
B |
8313 |
16542 |
|
B |
8314 |
16543 |
|
B |
8316 |
16553 |
|
B |
8351 |
16554 |
|
B |
8353 |
16555 |
|
B |
8356 |
16556 |
|
B |
8358 |
30350 |
|
B |
22322 |
32877 |
|
B |
20874 |
32878 |
|
B |
20873 |