Ошибка столбец не существует postgresql

Definition of the PostgreSQL column does not exist exception.

PostgreSQL column does not exist exception occurs when we have used a column that did not exist in the table, or it will occur when the used column name has a lower case name, and we have used upper case in our query. We can avoid this exception in many ways, like double-quote the column name for which column we have to get the exception. We can also check the column name which existed in the table or not. If the column name does not exist in the table, then we need to create the same into the table.

Syntax:

Below is the column name syntax that does not exist except in PostgreSQL.

• Column name does not exist exception using select

Select name_of_column from name_of_table limit (number);

1. Error: column name_of_column does not exist
2. Line1: select name_of_column from name_of_table limit (number);

• Column name does not exist exception using insert

Insert into name_of_table (name_of_column1, name_of_column2, name_of_column3, …, name_of_columnN) values (Value_of_column1, Value_of_column2, Value_of_column3, …, Value_of_columnN);

1. ERROR: column “name_of_column” does not exist
2. LINE 1: insert into name_of_table (name_of_column1, name_of_column2, name_of_column3, …, name_of_columnN) values (Value_of_column1, Value_of_column2, Value_of_column3, …, Value_of_columnN)

• Column name does not exist exception using update

update name_of_table set name_of_column = (value_of_column) where condition;

1. ERROR: column “name_of_column” does not exist
2. LINE 1: update name_of_table set name_of_column = value_of_column where name_of_column = ‘value_of_column’;

• Column name does not exist exception using delete

Delete from name_of_table where name_of_column = value_of_column;

1. ERROR: column “name_of_column” does not exist
2. LINE 1: delete from name_of_table where name_of_column = value_of_column;

Below is the parameter description syntax of column name does not exist exception in PostgreSQL.

• Select –Column name does not exist, an exception will display while we have to execute a select operation on the specified column.
• Insert – Column name does not exist exception will display while we have to execute insert operation on a specified column.
• Update – Column name does not exist exception will display while we have to execute update operation on the specified column.
• Delete – Column name does not exist exception will display while we have to execute delete operation on the specified column.
• Name of the column –This is defined as the column name from which we have received the exception that the column name does not exist.
• Name of the table –This is defined as the table name from which we have received the exception that the column name does not exist.

How column does not exist exception raised in PostgreSQL?

• The column does not exist exception occurs when a column does not exist in the table. If the searching column does not exist in the table, then it will raise the exception that the column does not exist in the table.
• The below example shows that if a searching column does not exist in the table, it will give the exception that the column name does not exist.

d+ test_col;
select ID_Name from test_col;

• In the above example, we have used the ID_Name column for searching the data from the test_col table, but it will issues an error that the column name does not exist in the table because the ID_Name column does not exist in the table.
• To select, update, delete, and insert the data into the table, we need to define the correct column name, which we searched for.
• Also, we need to define the column name in a double quote if our column name contains a mixed letter.
• The example below shows that we need to define the double quote when using a mixed letter column in operations.

select address from test_col;
d+ test_col;

• In the above example, we have used the address column, which contains the mixed letter, after using this column, it will issue an error because it will contain the mixed column letter.

Examples

• Below is an example of a column that does not exist exception. We have using a test_col table to describe an example of a column name that does not exist exception.
• Below are the data and table structure of the test_col table.

select * from test_col;
d+ test_col;

1. Column name does not exist exception using select

• The below example shows that the column name does not exception using select operations.

select Name, ID from test_col;
select "Name", "ID" from test_col;

2. Column name does not exist exception using insert

• The below example shows that the column name does not exception using insert operations.

insert into test_col (ID, Name, AddRess, PhoNe) values (3, 'ABC', 'Mumbai', 1234567890);
insert into test_col ("ID", "Name", "AddRess", "PhoNe") values (4, 'PQR', 'Mumbai', 1234567890);

3. Column name does not exist exception using update

• The below example shows that the column name does not exception using update operations.

update test_col set ID = 5 where Name = 'ABC';
update test_col set "ID" = 5 where "Name" = 'ABC';
select * from test_col;

4. Column name does not exist exception using delete

• The below example shows that the column name does not exception using delete operations.

delete from test_col where ID = 4;
delete from test_col where "ID" = 4;
select * from test_col;

How to avoid a column that does not exist exception?

• We can avoid the column does not exist exception by specifying the name of the column. Below is the example to avoid the column does not exist exception.

select test_name from test_col;
select "Name" from test_col;

• We can also avoid the exception by using the double quote in the column. Below example shows that use a double quote to avoid exception.

select Name from test_col;
select "Name" from test_col;

Conclusion

The column does not exist exception occurs in PostgreSQL when we have not used a specified column name while doing any operations. Also, it occurs when we have not used a double quote to the mismatch case letter column name in PostgreSQL.

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