形如"sdhj,fsda,sdf,sdaf,"的C语言字符串，如何已，为分割符，将字符串区分出来 已C语言代码实现一下

可以使用字符串分割函数`strtok`实现字符串的分割，具体实现代码如下：

#include <stdio.h>
#include <string.h>

int main() {
    char str[] = "sdhj,fsda,sdf,sdaf,";
    char *token = strtok(str, ",");
    while (token != NULL) {
        printf("%s\n", token);
        token = strtok(NULL, ",");
    }
    return 0;
}

输出结果为：

sdhj
fsda
sdf
sdaf

其中，`strtok`函数的第一个参数为需要分割的字符串，第二个参数为分割符。函数会将第一个参数中的字符串按照第二个参数中指定的分割符进行分割，并返回分割后的子字符串。在第一次调用函数时，第一个参数为需要分割的字符串，之后每次调用函数时，第一个参数为`NULL`，函数会在上一次调用结束的位置继续分割字符串。

相关问题

SELECT DISTINCT ( A.DATA_TYPE ) AS DATA_TYPE, A.DATA_VALUE AS TSL, IFNULL(( SELECT B.DATA_VALUE FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA B WHERE B.IS_DELETED = 0 AND B.DATA_DIMENSION = '期末' AND B.LEVEL = 2 AND B.DATA_NAME = '举报' AND B.DATA_AREA = '市级' AND B.DATA_TYPE = A.DATA_TYPE AND B.DATA_TIME = ( SELECT MAX( DATA_TIME ) FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA WHERE IS_DELETED = 0 AND DATA_DIMENSION = '期末' AND DATA_NAME = '举报' AND LEVEL = 2 AND DATA_AREA = '市级' ) ), 0 ) AS JBL, CURRENT_ID FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA A WHERE A.IS_DELETED = 0 AND A.DATA_DIMENSION = '期末' AND A.LEVEL = 2 AND A.DATA_NAME = '投诉' AND A.DATA_AREA = '市级' AND A.DATA_TIME = ( SELECT MAX( DATA_TIME ) FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA WHERE IS_DELETED = 0 AND DATA_DIMENSION = '期末' AND DATA_NAME = '投诉' AND LEVEL = 2 AND DATA_AREA = '市级')这个sql 优化

对于这个SQL查询语句的优化，可以考虑以下几点：

1. 使用JOIN语句代替子查询：将子查询转换为JOIN语句，可以提高查询性能。

2. 添加适当的索引：根据查询条件和连接条件，为相关表添加合适的索引，以加快查询速度。

3. 减少重复的条件判断：在子查询和主查询中，有一些条件判断是重复的，可以将它们提取出来，避免重复计算。

4. 使用表别名：为表和字段使用简短的别名，提高查询语句的可读性。

下面是对原始SQL查询语句进行优化的示例：

SELECT DISTINCT
A.DATA_TYPE AS DATA_TYPE,
A.DATA_VALUE AS TSL,
IFNULL(B.DATA_VALUE, 0) AS JBL,
A.CURRENT_ID
FROM
YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA A
LEFT JOIN
(
SELECT
DATA_TYPE, DATA_VALUE
FROM
YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA
WHERE
IS_DELETED = 0
AND DATA_DIMENSION = '期末'
AND DATA_NAME = '举报'
AND LEVEL = 2
AND DATA_AREA = '市级'
AND DATA_TIME = (
SELECT MAX(DATA_TIME)
FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA
WHERE
IS_DELETED = 0
AND DATA_DIMENSION = '期末'
AND DATA_NAME = '举报'
AND LEVEL = 2
AND DATA_AREA = '市级'
)
) B ON A.DATA_TYPE = B.DATA_TYPE
WHERE
A.IS_DELETED = 0
AND A.DATA_DIMENSION = '期末'
AND A.LEVEL = 2
AND A.DATA_NAME = '投诉'
AND A.DATA_AREA = '市级'
AND A.DATA_TIME = (
SELECT MAX(DATA_TIME)
FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA
WHERE
IS_DELETED = 0
AND DATA_DIMENSION = '期末'
AND DATA_NAME = '投诉'
AND LEVEL = 2
AND DATA_AREA = '市级'
);

请注意，具体的优化策略可能需要根据实际情况进行调整和测试，以达到最佳的查询性能。

SELECT DISTINCT(A.DATA_TYPE)as DATA_TYPE, A.DATA_VALUE as TSL,IFNULL((SELECT B.DATA_VALUE FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA B WHERE B.IS_DELETED = 0 AND B.DATA_DIMENSION = '期末'and B.level=2 and B.DATA_NAME='举报' AND B.DATA_AREA = '市级' AND B.DATA_TYPE=A.DATA_TYPE AND B.DATA_TIME = ( SELECT MAX(DATA_TIME) FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA WHERE IS_DELETED = 0 AND DATA_DIMENSION = '期末'and DATA_NAME='举报'and level=2 AND DATA_AREA = '市级' ) ),0)AS JBL,CURRENT_ID FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA A WHERE A.IS_DELETED = 0 AND A.DATA_DIMENSION = '期末'and A.level=2 and A.DATA_NAME='投诉' AND A.DATA_AREA = '市级' AND A.DATA_TIME = ( SELECT MAX(DATA_TIME) FROM YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA WHERE IS_DELETED = 0 AND DATA_DIMENSION = '期末'and DATA_NAME='投诉'and level=2 AND DATA_AREA = '市级' ) 这是SQL 要查询什么

根据你提供的SQL查询语句，它的目标是从表 `YXDDZH_MIDDLE.GZ_SCREEN_JGSY_SDHJ_SPFW_CITY_AREA_DATA` 中查询符合条件的数据，并返回以下字段：

- `DATA_TYPE`：作为去重后的数据类型
- `TSL`：数据值
- `JBL`：如果存在满足条件的举报数据，则返回该数据值，否则返回0
- `CURRENT_ID`

该查询语句的条件如下：

- `IS_DELETED = 0`：筛选未被删除的记录
- `DATA_DIMENSION = '期末'`：筛选数据维度为期末的记录
- `level = 2`：筛选级别为2的记录
- `DATA_NAME = '投诉'`：筛选数据名称为投诉的记录
- `DATA_AREA = '市级'`：筛选数据区域为市级的记录
- 通过子查询获取满足条件的最大 `DATA_TIME`

请注意，这只是根据你提供的查询语句进行的分析，具体的查询结果会根据你的数据库中实际数据而有所不同。如果你有其他要求或需要更详细的解释，请提供更多信息。