Shulou(Shulou.com)06/01 Report--

Analysis 2:

There are a large number of multi-table joins in this SQL. Because the algorithm of statistical information of MSSQL engine is single, when dealing with a large number of cascading joins, the actual data may seriously deviate from the statistical information.

There is a serious inconsistency between Actual Rows and Estimated Rows in the connection, which becomes more serious as the number of join tables increases:

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