Greenplum函数 - 身份证号15位转18位

前几天一直有人在问，如何在Greenplum里面实现身份证号15位到18位的转换函数，今天网上搜了一下，看了看大概的逻辑，做了个简单实现，转换逻辑不懂的，请自行百度吧，这里放出函数内容，供大家使用：

函数：

-- Function: idcard15to18(character)
-- DROP FUNCTION idcard15to18(character);

CREATE OR REPLACE FUNCTION idcard15to18(card character)
  RETURNS character AS
$BODY$declare
    W int[];
    A char[];
    S integer;
    RESULTS char(18);

begin
    if CARD is null then
        return '';
    end if;
    if length(CARD) <> 15 then
        return CARD;
    end if;
    W := array[7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2];
    A := array['1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'];
    RESULTS := substr(CARD, 1, 6)||'19'||substr(CARD, 7, 9);
    S := 0;
    begin
        for i in 1..17 loop
            S := S+substr(RESULTS, i, 1)::int*W[i];
        end loop;
    exception
        when Others then
            return '';
    end;
    S := mod(S,11);
    RESULTS := RESULTS||A[S+1];
    return(RESULTS);
end;$BODY$
  LANGUAGE plpgsql VOLATILE;
ALTER FUNCTION idcard15to18(character)
  OWNER TO dgadmin;
COMMENT ON FUNCTION idcard15to18(character) IS '身份证15位转18位函数';

示例：

tpch1g=# select  idcard15to18('123456789123456');
    idcard15to18
--------------------
 12345619789123456X
(1 row)

End~