MySQL—函数方法汇总.ipynb

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    "## Sql函数方法\n",
    "　　参考：[MySQL—字符串拆分（含分隔符的字符串截取）](https://blog.csdn.net/pjymyself/article/details/81668157?utm_medium=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromMachineLearnPai2-1.channel_param&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromMachineLearnPai2-1.channel_param)<BR>\n",
    "    \n",
    "### 1、SUBSTRING_INDEX（str, delim, count）\n",
    "　　含分隔符的字符串拆分\n",
    "\n",
    "|参数名|解释|\n",
    "|:--- |:--- |\n",
    "|str|需要拆分的字符串|\n",
    "|delim|分隔符，通过某字符进行拆分|\n",
    "|count|当 count 为正数，取第 n 个分隔符之前的所有字符； 当 count 为负数，取倒数第 n 个分隔符之后的所有字符。|\n",
    "\n",
    "#### 1.1、获取第2个以“，”逗号为分隔符之前的所有字符。\n",
    "SUBSTRING_INDEX('7654,7698,7782,7788',',',2)\n",
    "#### 1.2、获取倒数第2个以“，”逗号分隔符之后的所有字符\n",
    "SUBSTRING_INDEX('7654,7698,7782,7788',',',-2)\n",
    "\n",
    "### 2、replace( str, from_str, to_str)\n",
    "　　替换函数\n",
    "\n",
    "|参数名|解释|\n",
    "|:--- |:--- |\n",
    "|str|\t需要进行替换的字符串|\n",
    "|from_str|\t需要被替换的字符串|\n",
    "|to_str|\t需要替换的字符串|\n",
    "    \n",
    "#### 2.1、将分隔符“，”逗号替换为“”空。\n",
    "REPLACE('7654,7698,7782,7788',',','')\n",
    "\n",
    "### 3、LENGTH( str )\n",
    "　　获取字符串长度\n",
    "\n",
    "|参数名|\t解释|\n",
    "|:--- |:--- |\n",
    "|str|需要计算长度的字符串|\n",
    "    \n",
    "#### 3.1、获取 ‘7654,7698,7782,7788’ 字符串的长度\n",
    "LENGTH('7654,7698,7782,7788')\n",
    "\n"
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