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24.8. UNION

union 分页问题

(SELECT a FROM tbl_name_a WHERE a=10 AND B=1)
UNION
(SELECT a FROM tbl_name_b WHERE a=11 AND B=2)
ORDER BY a LIMIT 10;
		
select * from (
	select a from tbl_name_a WHERE a=10 AND B=1
	union all
	select a from tbl_name_b WHERE a=10 AND B=1
) tbl_name
order by a limit 0,1;
		

24.8.1. UNION ALL

UNION ALL 不会合并重复的记录

select a,b from tbl_name_a WHERE a=10 AND B=1
union all
select a,b from tbl_name_b WHERE a=10 AND B=1
			

24.8.2. 两张表字段不对等解决方法

			
SELECT * FROM
    (
    SELECT contract_address, decimals, name, symbol, seq, logo FROM token 
    UNION 
    SELECT contract_address, decimals, name, symbol, 100, 'https://www.netkiller.cn/images/eth.jpg' FROM user_token WHERE address = '0xB94054c174995AE2A9E7fcf6c7924635FBa8ECF7' AND contract_address NOT IN (SELECT contract_address FROM token)
    ) AS tmp
ORDER BY seq