Question

我是ms sql的初学者，我有两张桌子第一张表有

id param1 indicator1 indicator2
1  a      1          2
2  z      3          4
2  z      7          2
3  a      8          9
4  z      7          9
5  y      9          6

第二张表有

Param  Indicator
a      1
b      2
null   3
null   4

我想要一个可以实现此目的的结果集：

For each row in table 1

if( param1 is in Param column)

    print row from table 1
  else 
   if(indicator1 in indicator column_
      print row from table 1
   if(indicator2 in indicator column)
     print row from table 1

因此得到的数据集将是

id param1 indicator1 indicator2
1  a      1          2
2  z      3          4
2  z      7          2
3  a      8          9

我想要一个更有效的解决方案

select distinct id, param1, indicator1, indicator2 
from table1 t1, table2 t2   
where param1= param or indicator1 = indicator or indicator2 = indicator

Answer 1

而不是Join来检查是否存在使用性能更好的EXISTS。

SELECT *
FROM   table1 t
WHERE  EXISTS (SELECT 1
               FROM   table2 s
               WHERE  t.param1 = s.Param
                       OR t.indicator1 = s.Indicator
                       OR t.indicator2 = s.Indicator)

Answer 2

使用 JOIN 代替逗号分隔的表：

SELECT DISTINCT Id, param1, indicator1, indicator2
FROM table1 t1
JOIN table2 t2 ON t1.param1 = t2.Param OR 
                  t1.indicator1 = t2.indicator OR 
                  t1.indicator2 = t2.indicator

<强>输出：

id param1 indicator1 indicator2
1  a      1          2
2  z      3          4
2  z      7          2
3  a      8          9

<强> SQL FIDDLE

Answer 3

SELECT * FROM TABLE1 tbl1 INNER JOIN TABLE2 tbl2 on tbl1.param1 = tbl2.param

Answer 4

SELECT * FROM table1 t1 INNER JOIN table2 t2 ON t1.id = t2.indicator

匹配多个表ms sql中的列

4 个答案: