есть необходимость найти среднее значение по полю. но чет не пролучается. тип поля текст, но там число лежит

SELECT
"ID_TagData",
"F_TagName_ID",
"F_Conversion_ID",
"F_Value",
"F_Date",
avg("F_ConvertedValue")
FROM
"SC_Tag"."T_TagData" where "F_TagName_ID" =46 or "F_TagName_ID" =45 order by "ID_TagData" desc limit 100;


ERROR: function avg(text) does not exist
LINE 1: ...Name_ID", "F_Conversion_ID", "F_Value", "F_Date", avg("F_Con...
^
HINT: No function matches the given name and argument types. You might need to add explicit type casts.

SELECT
"ID_TagData",
"F_TagName_ID",
"F_Conversion_ID",
"F_Value",
"F_Date",
avg("F_ConvertedValue"::real) as gx
FROM
"SC_Tag"."T_TagData" where "F_TagName_ID" =46 or "F_TagName_ID" =45 order by "ID_TagData" desc limit 100;


ERROR: syntax error at or near ":"
LINE 1: ...n_ID", "F_Value", "F_Date", avg("F_ConvertedValue":real) as ...
^

SELECT
"ID_TagData",
"F_TagName_ID",
"F_Conversion_ID",
"F_Value",
"F_Date",
avg(cast ("F_ConvertedValue" as real))
FROM
"SC_Tag"."T_TagData" where "F_TagName_ID" =46 or "F_TagName_ID" =45 order by "ID_TagData" desc limit 100;


ERROR: column "T_TagData.ID_TagData" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: SELECT "ID_TagData", "F_TagName_ID", "F_Conversion_ID", "F_V...
^

SELECT
"ID_TagData",
"F_TagName_ID",
"F_Conversion_ID",
"F_Value",
"F_Date",
avg(cast ("F_ConvertedValue" as real))
FROM
"SC_Tag"."T_TagData" where "F_TagName_ID" =46 or "F_TagName_ID" =45 group by "ID_TagData" ;

так заработало