情况一
Table 'lead_transaction'. Scan count 10, logical reads 394, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'appt_master'. Scan count 20, logical reads 4532, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
情况2
Table 'lead_transaction'. Scan count 36466, logical reads 117088, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'appt_master'. Scan count 36466, logical reads 195492, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
情况 1查询在4 秒内执行,使用左连接
&
在情况 2查询在 3 秒内执行,使用外部应用,但逻辑读取非常高。
那么从性能上来说什么是好的呢?