Question

我有一张如下表格

table1
---------    
x   y  z   total  average
========================
1   2  3 
2   3  4 
3   4  5

这里我只需要在前端对应列中选择列需要一个总和平均例如，如果我选择前端的x，y，total，average列我需要一个如下所示的输出

x    y   total  avg
1    2    3     1.5
2    3    5     2.5
3    4    7     3.5

这里使用refcursor with dynamicsql

create or replace function sample_refcursor(i_column in varchar) returns refcursor as

$$
declare
c1 refcursor;
begin

drop   table if exists temp_t;
create  temp table temp_t as select x as A,y as B,z as C,total as tot,avg as average from table1;

open c1 for execute('select ' ||i_column|| ' from temp_t group by ' ||i_column);
return c1;
close c1;
end;
$$ language plpgsql

Answer 1

您可以尝试：SELECT x,y, x+y AS total, (x+y)/2 AS average FROM Table;

Answer 2

SELECT x, y, x+y AS tot, (x+y)/2 AS Avg From TableName

我按照你的第二张表，你没有使用z。

使用以下代码

<?php
// Connecting, selecting database
$dbconn = pg_connect("host=localhost dbname=publishing user=www password=foo")
    or die('Could not connect: ' . pg_last_error());

// Performing SQL query
$query = 'SELECT x, y, x+y AS tot, (x+y)/2 AS Avg From TableName';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());

// Printing results in HTML
echo "<table>\n";
while ($line = pg_fetch_array($result, null, PGSQL_ASSOC)) {
    echo "\t<tr>\n";
    foreach ($line as $col_value) {
        echo "\t\t<td>$col_value</td>\n";
    }
    echo "\t</tr>\n";
}
echo "</table>\n";

// Free resultset
pg_free_result($result);

// Closing connection
pg_close($dbconn);
?>

如何获取所选列的数据？

2 个答案: