1：经纬度计算距离
DECLARE
dx float8;
dy float8;
b float8;
Lx float8;
Ly float8;
begin
dx := lng1 - lng2;
dy := lat1 - lat2;
b := (lat1 + lat2) * 0.5;
Lx := RADIANS(dx) * 6367000.0 * COS(RADIANS(b));
Ly := 6367000.0 * RADIANS(dy);
RETURN SQRT(Lx * Lx + Ly * Ly);
END
2，随机生成字符串
declare
chars text[] := '{0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z}';
result text := '';
i integer := 0;
begin
if length < 0 then
raise exception 'Given length cannot be less than 0';
end if;
for i in 1..length loop
result := result || chars[1+random()*(array_length(chars, 1)-1)];
end loop;
return result;
end;
3：时间转换
DECLARE
result BIGINT;
BEGIN
result := extract(epoch FROM date_trunc('minute', to_timestamp(datestr, 'YYYY-MM-DD HH24:MI:SS')));
RETURN result * 1000;
END;