摘要:case 1、例: select u.uid,case when u.birthday>='1990' and u.birthday<='1999' then '90 后' when u.birthday>='1980' and u.birthday<='1989' then '80 后' when
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摘要:1、concat() 1.1、concat(str1, str2, ...) user表 id name 01 test 运行:select concat(id, ',', name) as info from user 结果 info 01,test 1.2、concat_ws(separator
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