优化SQL语句：根据项目状态和时间统计数据

{/'title/':/'优化SQL语句：根据项目状态和时间统计数据/',/'description/':/'本篇文章介绍了如何优化一个复杂的SQL语句，并分析了常见的优化方法，如使用表别名、内连接、CASE语句等。通过优化后，SQL语句的执行效率将会得到提升。/',/'keywords/':/'SQL优化, 表别名, 内连接, CASE语句, 子查询, 索引优化/',/'content/':/'SELECT x.C_VILID, x.C_VILNAME, SUM(x.m9) AS m9_x, SUM(x.m1) AS m1_x, SUM(x.m2) AS m2_x, SUM(x.m3) AS m3_x, SUM(x.m4) AS m4_x, SUM(x.m5) AS m5_x, SUM(x.m6) AS m6_x, SUM(x.m7) AS m7_x, SUM(x.m8) AS m8_x, SUM(CASE WHEN x.C_PROJECTSTATUS = 1 THEN 1 ELSE 0 END) AS finish, SUM(CASE WHEN x.C_PROJECTSTATUS = 0 THEN 1 ELSE 0 END) AS nofinish, y.C_PLACEID, SUM(y.m9) AS m9_y, SUM(y.m1) AS m1_y, SUM(y.m2) AS m2_y, SUM(y.m3) AS m3_y, SUM(y.m4) AS m4_y, SUM(y.m5) AS m5_y, SUM(y.m6) AS m6_y, SUM(y.m7) AS m7_y, SUM(y.m8) AS m8_y FROM (SELECT x.C_VILID, x.C_VILNAME, x.C_PROJECTSTATUS, x.m9, x.m1, x.m2, x.m3, x.m4, x.m5, x.m6, x.m7, x.m8 FROM db_twenty.t_projectreports x WHERE x.C_TOWID = 441424137000 AND x.R_STATEMENT_ID = 47 AND x.C_DELETED = 0) x LEFT JOIN (SELECT x.C_VILID AS C_PLACEID, x.m9, x.m1, x.m2, x.m3, x.m4, x.m5, x.m6, x.m7, x.m8 FROM db_twenty.t_projectreports x WHERE x.C_TOWID = 441424137000 AND x.C_ANNUAL * 100 + x.C_PERIOD <= 202305 AND x.C_DELETED = 0) y ON x.C_VILID = y.C_PLACEID GROUP BY x.C_VILID, x.C_VILNAME, y.C_PLACEID/