需求：
将数据库中的markdown文本导出后换行符变成了“\n”,再导入到其他数据库时需要将\n转成数据库中的换行。
语法：
update 表名 set 字段名=REPLACE(字段名,X'0D'||X'0A','要添加的部分'||X'0D'||X'0A');
方法：
在sqlite中 换行符 为x’0a’
Sqlite 字段替换换行符 方法为：
update table set title =replace(title, x'0a','')
解释：
其实，在sqlite中特殊的字符是ASCLL码，如果想替换回车字符改成13，可以如下写法：
UPDATE table_name SET field_name=REPLACE(field_name,char(13),'')
UPDATE table_name SET field_name=REPLACE(field_name,x'13'，‘')
| 二进制 | Decode | Hex 缩写/字符 | 解释 |
|---|---|---|---|
| 0 | 0 0 | 0 | NUL(null) 空字符 |
| 1 | 1 0 | 1 | SOH(start of headling) 标题开始 |
| 10 | 2 0 | 2 | STX (start of text) 正文开始 |
| 11 | 3 0 | 3 | ETX (end of text) 正文结束 |
| 100 | 4 0 | 4 | EOT (end of transmission) 传输结束 |
| 101 | 5 0 | 5 | ENQ (enquiry) 请求 |
| 110 | 6 0 | 6 | ACK (acknowledge) 收到通知 |
| 111 | 7 0 | 7 | BEL (bell) 响铃 |
| 1000 | 8 0 | 8 | BS (backspace) 退格 |
| 1001 | 9 0 | 9 | HT (horizontal tab) 水平制表符 |
| 1010 | 10 | 0A | LF (NL line feed, new line) 换行键 |
| 1011 | 11 | 0B | VT (vertical tab) 垂直制表符 |
| 1100 | 12 | 0C | FF (NP form feed, new page) 换页键 |
| 1101 | 13 | 0D | CR (carriage return) 回车键 |
| 1110 | 14 | 0E | SO (shift out) 不用切换 |
| 1111 | 15 | 0F | SI (shift in) 启用切换 |
| 10000 | 16 | 10 | DLE (data link escape) 数据链路转义 |
| 10001 | 17 | 11 | DC1 (device control 1) 设备控制1 |
| 10010 | 18 | 12 | DC2 (device control 2) 设备控制2 |
| 10011 | 19 | 13 | DC3 (device control 3) 设备控制3 |
| 10100 | 20 | 14 | DC4 (device control 4) 设备控制4 |
| 10101 | 21 | 15 | NAK (negative acknowledge) 拒绝接收 |
| 10110 | 22 | 16 | SYN (synchronous idle) 同步空闲 |
| 10111 | 23 | 17 | ETB (end of trans. block) 传输块结束 |
| 11000 | 24 | 18 | CAN (cancel) 取消 |
| 11001 | 25 | 19 | EM (end of medium) 介质中断 |
| 11010 | 26 | 1A | SUB (substitute) 替补 |
| 11011 | 27 | 1B | ESC (escape) 溢出 |
| 11100 | 28 | 1C | FS (file separator) 文件分割符 |
| 11101 | 29 | 1D | GS (group separator) 分组符 |
| 11110 | 30 | 1E | RS (record separator) 记录分离符 |
| 11111 | 31 | 1F | US (unit separator) 单元分隔符 |
| 100000 | 32 | 20 | (space) 空格 |
| 100001 | 33 | 21 | ! |
| 100010 | 34 | 22 | " |
| 100011 | 35 | 23 | # |
| 100100 | 36 | 24 | $ |
| 100101 | 37 | 25 | % |
| 100110 | 38 | 26 | & |
| 100111 | 39 | 27 | ’ |
| 101000 | 40 | 28 | ( |
| 101001 | 41 | 29 | ) |
| 101010 | 42 | 2A | * |
| 101011 | 43 | 2B | + |
| 101100 | 44 | 2C | , |
| 101101 | 45 | 2D | - |
| 101110 | 46 | 2E | . |
| 101111 | 47 | 2F | / |
| 110000 | 48 | 30 | 0 |
| 110001 | 49 | 31 | 1 |
| 110010 | 50 | 32 | 2 |
| 110011 | 51 | 33 | 3 |
| 110100 | 52 | 34 | 4 |
| 110101 | 53 | 35 | 5 |
| 110110 | 54 | 36 | 6 |
| 110111 | 55 | 37 | 7 |
| 111000 | 56 | 38 | 8 |
| 111001 | 57 | 39 | 9 |
| 111010 | 58 | 3A | : |
| 111011 | 59 | 3B | ; |
| 111100 | 60 | 3C | < |
| 111101 | 61 | 3D | = |
| 111110 | 62 | 3E | > |
| 111111 | 63 | 3F | ? |
| 1000000 | 64 | 40 | @ |
| 1000001 | 65 | 41 | A |
| 1000010 | 66 | 42 | B |
| 1000011 | 67 | 43 | C |
| 1000100 | 68 | 44 | D |
| 1000101 | 69 | 45 | E |
| 1000110 | 70 | 46 | F |
| 1000111 | 71 | 47 | G |
| 1001000 | 72 | 48 | H |
| 1001001 | 73 | 49 | I |
| 1001010 | 74 | 4A | J |
| 1001011 | 75 | 4B | K |
| 1001100 | 76 | 4C | L |
| 1001101 | 77 | 4D | M |
| 1001110 | 78 | 4E | N |
| 1001111 | 79 | 4F | O |
| 1010000 | 80 | 50 | P |
| 1010001 | 81 | 51 | Q |
| 1010010 | 82 | 52 | R |
| 1010011 | 83 | 53 | S |
| 1010100 | 84 | 54 | T |
| 1010101 | 85 | 55 | U |
| 1010110 | 86 | 56 | V |
| 1010111 | 87 | 57 | W |
| 1011000 | 88 | 58 | X |
| 1011001 | 89 | 59 | Y |
| 1011010 | 90 | 5A | Z |
| 1011011 | 91 | 5B | [ |
| 1011100 | 92 | 5C | \ |
| 1011101 | 93 | 5D | ] |
| 1011110 | 94 | 5E | |
| 1011111 | 95 | 5F | _ |
| 1100000 | 96 | 60 | ` |
| 1100001 | 97 | 61 | a |
| 1100010 | 98 | 62 | b |
| 1100011 | 99 | 63 | c |
| 1100100 | 100 | 6 | 4 d |
| 1100101 | 101 | 6 | 5 e |
| 1100110 | 102 | 6 | 6 f |
| 1100111 | 103 | 6 | 7 g |
| 1101000 | 104 | 6 | 8 h |
| 1101001 | 105 | 6 | 9 i |
| 1101010 | 106 | 6 | A j |
| 1101011 | 107 | 6 | B k |
| 1101100 | 108 | 6 | C l |
| 1101101 | 109 | 6 | D m |
| 1101110 | 110 | 6 | E n |
| 1101111 | 111 | 6 | F o |
| 1110000 | 112 | 7 | 0 p |
| 1110001 | 113 | 7 | 1 q |
| 1110010 | 114 | 7 | 2 r |
| 1110011 | 115 | 7 | 3 s |
| 1110100 | 116 | 7 | 4 t |
| 1110101 | 117 | 7 | 5 u |
| 1110110 | 118 | 7 | 6 v |
| 1110111 | 119 | 7 | 7 w |
| 1111000 | 120 | 7 | 8 x |
| 1111001 | 121 | 7 | 9 y |
| 1111010 | 122 | 7 | A z |
| 1111011 | 123 | 7 | B { |
| 1111100 | 124 | 7 | C |
| 1111101 | 125 | 7 | D } |
| 1111110 | 126 | 7 | E ~ |
| 1111111 | 127 | 7 | F DEL (delete) 删除 |
