Mysql 仅当其中一个值具有空字段时，才在表中选择GROUP_BY和GROUP_CONCAT相同的值

我有一张满是姓名和地址的桌子。我想合并（group_concat）所有对城市状态和名称具有相同值的行，但前提是其中一个地址为空值。例如，我可能有以下表格：

name     |    addr    |  city  | state  | phone 

jon snow | 123 got st |  la    | CA     | 1234567890
jon snow | NULL       |  la    | CA     | 1225556789
walker   | 777 diff ln|  la    | CA     | 4556678899
walker   |456 crown rd|  la    | CA     | 33344455566

我希望结果是：

name     |    addr    |  city  | state  | phone

jon snow | 123 got st |  la    | CA     | 1234567890,1225556789
walker   | 777 diff ln|  la    | CA     | 4556678899
walker   |456 crown rd|  la    | CA     | 33344455566

目前我正在使用以下命令：

SELECT name, group_concat(distinct(addr)) as addr, city, state, group_concat(distinct phone) as phone from got_table group by name, city, state having count(*) >1;

即使有两个非空地址，也会将具有相同名称、城市、州的所有地址组合在一起。上述声明的结果如下：

name     |    addr                  |  city  | state  | phone

jon snow | 123 got st               |  la    | CA     | 1234567890,1225556789
walker   | 777 diff ln, 456 crown rd|  la    | CA     | 4556678899, 33344455566

---

是否有一种方法仅当行的地址之一为空时才合并，并且仅当只有两行匹配时才执行此组合并

您可以尝试使用子查询按

大小写分组

检查
addr
列是否
NULL
get

addr
为空获取
MAX
值或您的expect group by concat值
addr
不为空get
addr
像这样

CREATE TABLE got_table(
   name varchar(50),
   addr varchar(50),
  city varchar(50),
    state varchar(50),
    phone varchar(50)
); 


insert into got_table values ('jon snow','123 got st'  ,'la', 'CA', '1234567890');
insert into got_table values ('jon snow',NULL          ,'la', 'CA', '1225556789');
insert into got_table values ('walker','777 diff ln' ,'la', 'CA'  , '4556678899');
insert into got_table values ('walker','456 crown rd','la', 'CA'  , '33344455566');

查询1：

SELECT name,
       case when addr is null then
       (
         SELECT MAX(tt.addr) 
         FROM got_table tt
         WHERE t1.name = tt.name 
         and t1.city = tt.city 
         and t1.state = tt.state
       ) else addr end as address,
       city, 
       state, 
       group_concat(distinct phone) as phone 
from got_table t1
group by name, city, state,address

|     name |      address | city | state |                 phone |
|----------|--------------|------|-------|-----------------------|
| jon snow |   123 got st |   la |    CA | 1225556789,1234567890 |
|   walker | 456 crown rd |   la |    CA |           33344455566 |
|   walker |  777 diff ln |   la |    CA |            4556678899 |

：

SELECT name,
       case when addr is null then
       (
         SELECT MAX(tt.addr) 
         FROM got_table tt
         WHERE t1.name = tt.name 
         and t1.city = tt.city 
         and t1.state = tt.state
       ) else addr end as address,
       city, 
       state, 
       group_concat(distinct phone) as phone 
from got_table t1
group by name, city, state,address

|     name |      address | city | state |                 phone |
|----------|--------------|------|-------|-----------------------|
| jon snow |   123 got st |   la |    CA | 1225556789,1234567890 |
|   walker | 456 crown rd |   la |    CA |           33344455566 |
|   walker |  777 diff ln |   la |    CA |            4556678899 |

如果有三行具有相同的城市和州，并且其中一行在
addr
中具有
null
值，您希望发生什么？是否应返回两个带有非空
addr
的行，还是仅返回其中一行？此外，空
addr
行的
电话应继续执行这两个非空
addr
行中的哪一行？也就是说，如果您的数据中也有这一行
jon snow | 425 Kings way | la | CA | 1234567899
，那么结果应该是什么？我认为只有当只有两个地址时才会合并，一个是空的，另一个不是空的@ashermaxium