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SQL语句优化,该如何处理

www.myexceptions.net 网友分享于：2013-02-13 浏览：7次

SQL语句优化
SELECT COUNT (1)
FROM big_house
WHERE lsh_xm = 100000303 AND ywlx = 0
UNION ALL
SELECT COUNT (1)
FROM big_house
WHERE lsh_xm = 100000303 AND ywlx = 2
UNION ALL
SELECT COUNT (1)
FROM big_house
WHERE lsh_xm = 100000303 AND ywlx = 3
UNION ALL
SELECT COUNT (1)
FROM big_house
WHERE lsh_xm = 100000303 AND ywlx = 4;

谁有办法让这个SQL语句同步进行，并以列的形式显示在一行上。也就是让其整成一条SQL语句，同时查询效率要比较快

------解决方案--------------------
select count(ywlx), ywlx
from big_house
where
lsh_xm = 100000303 AND ywlx in(0,2,3,4)
group by ywlx

select count(ywlx)
from big_house
where
lsh_xm = 100000303 AND ywlx in(0,2,3,4)

------解决方案--------------------

SQL code

SELECT COUNT (1)
  FROM big_house
 WHERE lsh_xm = 100000303 AND ywlx IN( 0,2,3,4)
 GROUP BY ywlx
ORDER BY ywlx

------解决方案--------------------
SELECT COUNT (1)
 FROM big_house
WHERE lsh_xm = 100000303  and ywlx in(0,2,3,4)

------解决方案--------------------
探讨

SQL code
SELECT COUNT (1)
  FROM big_house
 WHERE lsh_xm = 100000303 AND ywlx IN( 0,2,3,4)
 GROUP BY ywlx
ORDER BY ywlx


------解决方案--------------------
SQL code
SELECT SUM(CASE WHEN ywlx=0 THEN 1 ELSE 0 ) 0,
       SUM(CASE WHEN ywlx=2 THEN 1 ELSE 0 ) 2,
       SUM(CASE WHEN ywlx=3 THEN 1 ELSE 0 ) 3,
       SUM(CASE WHEN ywlx=4 THEN 1 ELSE 0 ) 4 
  FROM big_house
 WHERE lsh_xm = 100000303 
   AND ywlx IN( 0,2,3,4)

------解决方案--------------------
SELECT SUM(CASE WHEN ywlx=0 THEN 1 ELSE 0 ) 0,
      SUM(CASE WHEN ywlx=2 THEN 1 ELSE 0 ) 2,
      SUM(CASE WHEN ywlx=3 THEN 1 ELSE 0 ) 3,
      SUM(CASE WHEN ywlx=4 THEN 1 ELSE 0 ) 4  
 FROM big_house
  WHERE lsh_xm = 100000303  
  AND ywlx IN( 0,2,3,4)

这个才是正确的


------解决方案--------------------

SELECT SUM(CASE WHEN ywlx=0 THEN 1 ELSE 0 ) 0,
      SUM(CASE WHEN ywlx=2 THEN 1 ELSE 0 ) 2,
      SUM(CASE WHEN ywlx=3 THEN 1 ELSE 0 ) 3,
      SUM(CASE WHEN ywlx=4 THEN 1 ELSE 0 ) 4  
 FROM big_house
  WHERE lsh_xm = 100000303  
  AND ywlx IN( 0,2,3,4)