INSERT INTO sample VALUES('1','Am G'haubach');

INSERT INTO sample VALUES('1','Am G''haubach');

/* Re-write invalid characters to their SQL-safe alternatives */
t = targetbuf;
for(s = buf; s <= lastchar; s++) {
switch(*s) {
case ''':
    /* *t++ = '\'; */
    *t++ = '''';
    break;
case '\':
    *t++ = '\';
    *t++ = '\';
    break;
case 'n':
    *t++ = '\';
    *t++ = 'n';
    break;
case 'r':
    *t++ = '\';
    *t++ = 'r';
    break;
case 't':
    *t++ = '\';
    *t++ = 't';
    break;
default:
    *t++ = *s;
}
}

int n_quotes = 0;
// Point to base of target buf ...
t = targetbuf;
while (*s) {
    switch (*s) {
        case ''':
            // Examine the next character in an attempt
            // to determine if this is a 'string context'
            if (*(s + 1) != ',' && *(s + 1) != ')' && n_quotes % 2 == 1) {
                // We are more than likely inside a string ...
                *(t++) = ''';
                *(t++) = ''';
            } else {
                *(t++) = *s;
                n_quotes++;
            }
            break;
        default:
            *(t++) = *s;
            break;
    }
    s++;
}
*t = '';
puts(targetbuf);

INSERT INTO sample VALUES('1', 'Am G''haubach');