CREATE OR REPLACE FUNCTION CnFirstChar(s character varying) RETURNS character varying AS $BODY$ declare retval character varying; c character varying; l integer; b bytea; w integer; begin l=length(s); retval=''; while l>0 loop c=left(s,1); b=convert_to(c,'GB18030')::bytea; if get_byte(b,0)<127 then retval=retval || upper(c); elsif length(b)=2 then begin w=get_byte(b,0)*256+get_byte(b,1); --汉字GBK编码按拼音排序，按字符数来查找，基于概率来说，效率应该比挨个强:) if w between 48119 and 49061 then --"J";48119;49061;942 retval=retval || 'J'; elsif w between 54481 and 55289 then --"Z";54481;55289;808 retval=retval || 'Z'; elsif w between 53689 and 54480 then --"Y";53689;54480;791 retval=retval || 'Y'; elsif w between 51446 and 52208 then --"S";51446;52208;762 retval=retval || 'S'; elsif w between 52980 and 53640 then --"X";52980;53640;660 retval=retval || 'X'; elsif w between 49324 and 49895 then --"L";49324;49895;571 retval=retval || 'L'; elsif w between 45761 and 46317 then --"C";45761;46317;556 retval=retval || 'C'; elsif w between 45253 and 45760 then --"B";45253;45760;507 retval=retval || 'B'; elsif w between 46318 and 46825 then --"D";46318;46825;507 retval=retval || 'D'; elsif w between 47614 and 48118 then --"H";47614;48118;504 retval=retval || 'H'; elsif w between 50906 and 51386 then --"Q";50906;51386;480 retval=retval || 'Q'; elsif w between 52218 and 52697 then --"T";52218;52697;479 retval=retval || 'T'; elsif w between 49896 and 50370 then --"M";49896;50370;474 retval=retval || 'M'; elsif w between 47297 and 47613 then --"G";47297;47613;316 retval=retval || 'G'; elsif w between 47010 and 47296 then--"F";47010;47296;286 retval=retval || 'F'; elsif w between 50622 and 50905 then--"P";50622;50905;283 retval=retval || 'P'; elsif w between 52698 and 52979 then--"W";52698;52979;281 retval=retval || 'W'; elsif w between 49062 and 49323 then--"K";49062;49323;261 retval=retval || 'K'; elsif w between 50371 and 50613 then --"N";50371;50613;242 retval=retval || 'N'; elsif w between 46826 and 47009 then--"E";46826;47009;183 retval=retval || 'E'; elsif w between 51387 and 51445 then--"R";51387;51445;58 retval=retval || 'R'; elsif w between 45217 and 45252 then --"A";45217;45252;35 retval=retval || 'A'; elsif w between 50614 and 50621 then --"O";50614;50621;7 retval=retval || 'O'; end if; end; end if; s=substring(s,2,l-1); l=l-1; end loop; return retval; end; $BODY$ LANGUAGE plpgsql IMMUTABLE; 原文链接：https://www.f2er.com/postgresql/194920.html