Oracle 数据库执行 select table_name,wm_concat(colum_name) as colum_name from all_tab_colums a group by a.table_name order by colum_name 语句报错提示 ORA-00932: inconsistent datatypes: expected- got CLOB
时间: 2024-03-09 17:49:05 浏览: 23
The reason you are getting the ORA-00932 error is because `wm_concat` returns a CLOB data type, which cannot be used in the `ORDER BY` clause. To fix this error, you can use the `DBMS_LOB.SUBSTR` function to convert the CLOB data type to a VARCHAR2 data type. Here is an updated version of your SQL query:
```
SELECT table_name, DBMS_LOB.SUBSTR(wm_concat(column_name), 4000) AS column_name
FROM all_tab_columns
GROUP BY table_name
ORDER BY column_name;
```
Note that the second parameter of `DBMS_LOB.SUBSTR` specifies the maximum length of the output string, so you can adjust it based on your needs.
相关问题
UPDATE table_name SET column_c = column_a + column_b;
这是一个 SQL 语句,用于更新表中的数据。它的作用是将表中每行的 column_c 列的值设置为 column_a 列的值与 column_b 列的值拼接后的结果。需要注意的是,这个语句中缺少了 SET 关键字,应该修改为:
```
UPDATE table_name SET column_c = CONCAT(column_a, column_b);
```
其中 CONCAT 是 MySQL 中用于字符串拼接的函数。
SELECT FLOOR(SUM(column_name)) FROM table_name; 有负号怎么办
如果要将带负号的MySQL求和结果的小数部分去除并保留负号,可以使用以下语句:
```
SELECT CONCAT(SIGN(SUM(column_name)), FLOOR(ABS(SUM(column_name)))) FROM table_name;
```
其中,`column_name`为需要求和的列名,`table_name`为表名。`SIGN`函数返回求和结果的符号,`ABS`函数返回求和结果的绝对值,`FLOOR`函数将求和结果的绝对值向下取整。最后,`CONCAT`函数将符号和整数部分组合成一个字符串,保留负号。