贴心猫(imcat) v5.4 --- 极轻、极简通用PHP网站系统！
sql语句效率比较
0: 3.87,4.22,3.84 catid in(SELECT catid FROM dzx_portal_category WHERE upid=''9'')
1: 0.82,0.86,0.80 catid in(''56'',''57'',''58'')
2: 0.87,0.85,0.86 (catid=56 Or catid=57 Or catid=58) [否定,代码太多，效率也不一定高]
3: 0.84,0.94,0.93 catid in(56,57,58)
4: 0.85,0.83,0.82 catid>55 AND catid<59 [否定,不一定连续]
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0.8x catid in(''56'',''57'',''58'')
4.xx catid in(SELECT catid FROM dzx_portal_category WHERE upid=''9'')