用正则表达式改小写为大写

对于常用的SQL语句，有时为了规整，必须让关键字大写，但对有的不规范的，我们可以用正则表达式修改为大写，具体步骤为：

1.定义要大写的关键字

const
  sMatch: array[1..34] of string = ('select', 'case', 'begin', 'and', 'from', 'where', 'update', 'delete',
    'left', 'join', 'full', 'right', 'inner', 'outer', 'declare', 'set', 'distinct', 'if', 'is', 'null','order',
    'group', 'by', 'asc', 'desc', 'or', 'exists', 'having', 'sum', 'count', 'average', 'ave', 'raise', 'error');

2.定义规则

for i := Low(sMatch) to High(sMatch) do

if Rgr.Exec(Memo1.Text) then
      repeat
        str := Rgr.Match[1];
        str1 := StringReplace(str1,str,UpperCase(str),[rfReplaceAll]);
      until not Rgr.ExecNext;
    Memo2.Text :=str1;

整个代码为：

var
  i: Integer;
  Rgr: TRegExpr;
  sExpr,str,str1: string;
begin
  Memo1.Lines.Clear;
  Memo1.Lines.Text := 'select * from delphi WHERE id=1 and kind=3' + #10#13
    + ' ordER By id';
  Rgr := TRegExpr.Create;
  try
    Rgr.ModifierI := True;
    for i := Low(sMatch) to High(sMatch) do
      sExpr := sExpr + sMatch[i] + '|';
    sExpr := '(' + Copy(sExpr, 1, Length(sExpr) - 1) + ')';
    Rgr.Expression :=sExpr;
    str1 :=Memo1.Text;
    if Rgr.Exec(Memo1.Text) then
      repeat
        str := Rgr.Match[1];
        str1 := StringReplace(str1,str,UpperCase(str),[rfReplaceAll]);
      until not Rgr.ExecNext;
    Memo2.Text :=str1;
  finally
    Rgr.Free;
  end;
end;