Question

表结构:

ID PID KEY VALUE
1 2 CITY NEW YORK
2 2 COUNTRY UNITED STATES
3 2 STATE NEW YORK
4 1 CITY NEW JERSEY

and so on.. what I want is to get/filter the Result like

Where (KEY = CITY and VALUE = NEW YORK) 
      AND (key = country AND VALUE= UNITED STATES)

这把死灰复燃!

Answer 1

页: 1

SELECT t1.*
FROM my_table t1
INNER JOIN my_table t2 ON t1.pid = t2.pid
WHERE t1.key =  city  and t1.value =  new york 
  AND t2.key =  country  and t2.value =  united states ;

Answer 2

因此,在同一个栏中,有一个不同类型的数值的表格,一个标明每个类别(PID)。这是否正确?

If that s so, then you re going to need a self-join here:

SELECT
    DISTINCT cityTable.PID
FROM
    tableName AS cityTable
JOIN
    tableName AS countryTable
    ON cityTable.PID = countryTable.PID
WHERE
    cityTable.key = "city"
    AND
    cityTable.value = "NEW YORK"
    AND
    countryTable.key = "country"
    AND
    countryTable.value = "UNITED STATES";

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