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/ *-- t1:id, id1, id2, id3, id4, id5, id6 of 2 or more records with NULL fields have a field in the T1 table, where id is the primary key. How to print a record id with one or more fields of NULL? In addition, how is it most convenient to read records sequentially in a stored procedure? Note: the primary key id is out of order or may be a string -- * / drop table if exists T1 politics create table T1 (id int,id1 int,id2 int,id3 int,id4 int,id5 int,id6 int) Insert T1 select1,1,1,1,1,null,null union all select 2 insert nullwagernullwagernullwagernullwagernullwagernullwagernullwagernullwagernullrewnwnlwnlwylwy2jy3 union all select 3jjjjjnwy3jpt3jpg 4jnullwagernullwagernullwagernullwagernullwagernullifornlwywagernullwagernullirewnlwlwlwnlwlwlwlwlwlwlwlwlwlwlwlwlwlwlwllwlwlwlwywlwlwlwlwlwlwlwlw Declare cur cursor for select id,case char_length (concat (ifnull (id1,'@'), ifnull (id2,'@'), ifnull (id3,'@'), ifnull (id4,'@'), ifnull (id5,'@'), ifnull (id6,'@')-char_length (concat (ifnull (id1,'@'), ifnull (id2,'@'), ifnull (id3,'@'), ifnull (id4,'@'), ifnull (id5,'@'), ifnull (id6) '@')),'@,') when 6 then 6 when 5 then 5 when 4 then 4 when 3 then 3 when 2 then 2 then 1 else 0 end as c from T1 Declare exit HANDLER for not found close cur; open cur;repeat fetch cur into idd,n_c;if (nexc > = 2) thenselect * from T1 where id=idd;end if; until 0 end repeat;close cur;end; $$delimiter / * +-+ | id | id1 | id2 | id3 | id4 | id5 | id6 | +-+ | 1 | 1 | 1 | | 1 | 1 | NULL | NULL | +-+ 1 row in set (0.10 sec) +-+ | id | id1 | | | id2 | id3 | id4 | id5 | id6 | +-+ | 2 | NULL | NULL | NULL | 1 | 2 | 3 | +-- | -- + 1 row in set (0.14 sec) +-+ | id | id1 | id2 | id3 | id4 | id5 | id6 | +- -+ | 5 | NULL | 3 | 4 | NULL | NULL | NULL | +-+ 1 row in set (0.17 sec) * / above is all the contents of the article "mysql asks for a sample analysis of two or more fields with NULL values" Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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