poStresql,string_agg()通过关联表加入
我通过第三个关联表链接了2个表:
TABLE NAME: lot
id | description | <other multiple columns> |
1 | descr_string_1 | ... |
2 | descr_string_2 | ... |
TABLE NAME: id_class
id | code | name |
1 | 01 | class_1 |
2 | 02 | class_2 |
3 | 03 | class_3 |
TABLE NAME: association_lot_id_class
lot_id | class_id |
1 | 1 |
1 | 2 |
2 | 3 |
我正在尝试根据lot
包含相关类别上的级别数据的新表格:
TABLE NAME: new_table_lot
id | description | <other multiple columns> | class_codes | class_names |
1 | descr_string_1 | ... | "01, 02" | "class_1, class_2" |
2 | descr_string_2 | ... | "03" | "class_3" |
我尝试使用String_agg具有基于其他SOF答案的不同(绝对是错误的)变化(例如 postgresql- /a>),但没有运气
SELECT alic.id_class_id, alic.lot_id, ic.code
FROM association_lot_id_class alic
JOIN id_class ic
JOIN (
SELECT id_class_id, string_agg(id.code, ',') AS codes
FROM codes
GROUP BY id_class)
I have 2 tables linked together via 3rd association table:
TABLE NAME: lot
id | description | <other multiple columns> |
1 | descr_string_1 | ... |
2 | descr_string_2 | ... |
TABLE NAME: id_class
id | code | name |
1 | 01 | class_1 |
2 | 02 | class_2 |
3 | 03 | class_3 |
TABLE NAME: association_lot_id_class
lot_id | class_id |
1 | 1 |
1 | 2 |
2 | 3 |
I'm trying to make a new table based on lot
containing concatenated data on related classes:
TABLE NAME: new_table_lot
id | description | <other multiple columns> | class_codes | class_names |
1 | descr_string_1 | ... | "01, 02" | "class_1, class_2" |
2 | descr_string_2 | ... | "03" | "class_3" |
I've tried to use string_agg with different (definitely, wrong) variations based on other SOF answers (e.g. PostgreSQL - JOIN on string_agg) but no luck
SELECT alic.id_class_id, alic.lot_id, ic.code
FROM association_lot_id_class alic
JOIN id_class ic
JOIN (
SELECT id_class_id, string_agg(id.code, ',') AS codes
FROM codes
GROUP BY id_class)
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