INSERT INTO wg_purchase_V001 PID Pc_GXName

The SQL statement you provided is not valid. There is a syntax error in the GROUP BY clause. The correct syntax should be:

INSERT INTO wg_purchase_V001 (
    PID,
    Pc_GXName,
    Pc_GXValue,
    Pc_Order,
    Pc_GXTotalValue,
    Pc_IsAuto,
    Pc_GxSort,
    Pc_GxPrice,
    Pc_GxNum,
    Pc_IsCheck,
    Pc_GXValue1,
    Pc_GXMan,
    Pc_LIDS,
    Pc_IsCf
)
SELECT
    653,
    ISNULL(Pl_GxSort1, ''),
    ISNULL(ROUND(SUM(IFNULL(pl_GXValue, 0)), 1), 0),
    ISNULL(MAX(pl_order), 0) pl_order,
    ISNULL(ROUND(SUM(IFNULL(pl_GXValue, 0)), 1), 0),
    0,
    ISNULL(Pl_GxSort1, ''),
    ISNULL(ROUND(SUM(IFNULL(pl_GXValue, 0)), 1), 0),
    1,
    0,
    ISNULL(expr),
    '欧国冬',
    '6515',
    1
FROM
    wg_purchaselist_V001
WHERE
    pid = 653
    AND Pl_GxSort1 = '06木工'
    AND (PLID IN (6515) OR Pl_GxSort3 = '欧国冬')
GROUP BY
    Pl_GxSort1;

The error you mentioned, "ISNULL(ROUND(SUM(IFNULL(pl_GXValue,0)),1),0)", is not a standalone SQL statement. It is part of the SELECT clause within the INSERT INTO statement