postgre在select语句中查看查询出来的字段类型
时间: 2024-05-11 21:13:50 浏览: 11
在PostgreSQL中,可以使用以下两种方式查看查询出来的字段类型:
1. 使用\gdesc命令
在执行select语句后,输入\gdesc命令,即可查看查询出来的字段类型。例如:
```
SELECT * FROM my_table;
\gdesc
```
该命令会返回查询结果的列名、数据类型等信息。
2. 使用pg_typeof函数
可以在查询语句中使用pg_typeof函数获取字段类型。例如:
```
SELECT column1, pg_typeof(column1) FROM my_table;
```
该语句会返回查询结果的column1列和该列的数据类型。
相关问题
postgre中如何查询字段信息同时查询出条数
在PostgreSQL中,可以使用以下语句查询字段信息同时查询出条数:
```
SELECT COUNT(*), column1, column2, ... FROM table_name;
```
其中,`column1, column2, ...` 为要查询的字段名,`table_name` 为要查询的表名。执行这个语句后,会返回包含两个字段的结果集,第一个字段为查询出的总条数,第二个字段为查询出的字段信息。
POSTGRE 查看表结构语句
可以使用以下语句来查看POSTGRE数据库中表的结构:
1. 使用INFORMATION_SCHEMA查询表的结构信息:
SELECT column_name, data_type, character_maximum_length
FROM INFORMATION_SCHEMA.columns
WHERE table_name = 'your_table_name';
2. 使用表oid查询表字段的定义:
SELECT t.typname AS type, a.attname AS field, a.attlen AS length, a.atttypmod AS lengthvar, a.attnotnull AS notnull, b.description AS comment
FROM pg_attribute a
LEFT OUTER JOIN pg_description b ON a.attrelid = b.objoid AND a.attnum = b.objsubid
JOIN pg_type t ON a.atttypid = t.oid
WHERE a.attnum > 0 AND a.attrelid = 'your_table_oid'
ORDER BY a.attnum;
3. 使用SQL方式查看表结构:
SELECT A.attnum, A.attname AS field, T.typname AS type, A.attlen AS length, A.atttypmod AS lengthvar, A.attnotnull AS notnull, b.description AS comment
FROM pg_class C
JOIN pg_attribute A ON A.attrelid = C.oid
LEFT OUTER JOIN pg_description b ON A.attrelid = b.objoid AND A.attnum = b.objsubid
JOIN pg_type T ON A.atttypid = T.oid
WHERE C.relname = 'your_table_name' AND A.attnum > 0
ORDER BY A.attnum;
请将上述语句中的'your_table_name'替换为你要查询的表名,'your_table_oid'替换为你要查询的表的oid。
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