如何在MySQL查询中使用OR

Question

我是SQL新手,无法理解为什么这个查询没有返回结果但是我知道这是因为我正在使用OR条件不正确.如果

有人可以请出示正确的方法来解决这个问题吗？

SELECT trddata.id, trddata.ts, instr.name, instr.underlying, instr.expiration,instr.strike, instr.callput,opnint.vol, trdind.name ind,exch.name exch, trddata.price,trddata.bidprcbbo,trddata.askprcbbo  
FROM trdopt trddata 
JOIN instropt instr 
ON trddata.optid = instr.id 
JOIN trdindopt trdind 
ON trdind.id = trddata.ind 
JOIN exchopt exch 
ON trddata.exchcode = exch.id 
JOIN opnintopt opnint 
ON opnint.optid = trddata.optid 
WHERE opnint.ds = DATE_FORMAT(trddata.ts, '%Y-%m-%d') 
AND trddata.id >= 71125752 
AND trddata.ts <= '2013-06-20 16:30:36' 
AND instr.underlying = 'AAPL'  
AND exch.name = 'AMEX'  
OR exch.name = 'CBOE'  
OR exch.name = 'ISE'  
OR exch.name = 'PHLX'  
ORDER BY trddata.id 
LIMIT 100;

Answer 1

看起来你想要一些括号:

AND (exch.name = 'AMEX'  
OR exch.name = 'CBOE'  
OR exch.name = 'ISE'  
OR exch.name = 'PHLX')

你也可以使用IN:

AND exch.name IN ('AMEX','CBOE','ISE','PHLX')

Answer 2

我认为你应该使用()例如

SELECT trddata.id, trddata.ts, instr.name, instr.underlying, instr.expiration,instr.strike, instr.callput,opnint.vol, trdind.name ind,exch.name exch, trddata.price,trddata.bidprcbbo,trddata.askprcbbo  
FROM trdopt trddata 
JOIN instropt instr 
ON trddata.optid = instr.id 
JOIN trdindopt trdind 
ON trdind.id = trddata.ind 
JOIN exchopt exch 
ON trddata.exchcode = exch.id 
JOIN opnintopt opnint 
ON opnint.optid = trddata.optid 
WHERE opnint.ds = DATE_FORMAT(trddata.ts, '%Y-%m-%d') 
AND trddata.id >= 71125752 
AND trddata.ts <= '2013-06-20 16:30:36' 
AND instr.underlying = 'AAPL'  
AND (exch.name = 'AMEX'  
OR exch.name = 'CBOE'  
OR exch.name = 'ISE'  
OR exch.name = 'PHLX')
ORDER BY trddata.id 
LIMIT 100;