1. Concat multiple fields splicing.
Such as: select concat('1','2','3') from test; result: 123
select concat(content_title,"|",content_price) from contents ;
2 , concat_ws(separator,str1,str2,…) multiple fields are spliced, the first parameter is the separator of other parameters
Such as: select concat_ws(':','1','2','3') from test; result: 1:2:3
select concat_ws("|",content_title,content_price,speaker) from contents ;
3 , group_concat multi-line result splicing
select group_concat(column_name)
from information_schema.columns
where table_schema='exchange' and table_name='bf_dd';
Other functions
substring intercept string:
substring(str, pos) Description: substring (the field to be intercepted, starting from the first few digits)
substring(str, pos, length) substring (the field to be intercepted, starting from the first few digits, and the length of the interception)
select substring(content,5) as abstract from my_content_t
select substring(content,5,200) as abstract from my_content_t