postgresql queries with expression - postgresql

I create this table 'friend' with PgAdmin III. I would like to select all the data where the word 'grand' is contained in the columns keywords.
I tried the following:
SELECT * FROM friend where keywords LIKE 'grand';
but it does not work, i don't receive any results.
Would someone have any ideas ?
Thank you

Use wildcards:
select *
from friend
where keywords like '%grand%';
Read more in the documentation.

Related

Postgres Copy csv to table sql [duplicate]

I'm trying to run the following PHP script to do a simple database query:
$db_host = "localhost";
$db_name = "showfinder";
$username = "user";
$password = "password";
$dbconn = pg_connect("host=$db_host dbname=$db_name user=$username password=$password")
or die('Could not connect: ' . pg_last_error());
$query = 'SELECT * FROM sf_bands LIMIT 10';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());
This produces the following error:
Query failed: ERROR: relation "sf_bands" does not exist
In all the examples I can find where someone gets an error stating the relation does not exist, it's because they use uppercase letters in their table name. My table name does not have uppercase letters. Is there a way to query my table without including the database name, i.e. showfinder.sf_bands?
From what I've read, this error means that you're not referencing the table name correctly. One common reason is that the table is defined with a mixed-case spelling, and you're trying to query it with all lower-case.
In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to the "search_path" so that when you reference a table name without qualifying its schema, the query will match that table name by checked each schema in order. Just like PATH in the shell or include_path in PHP, etc. You can check your current schema search path:
SHOW search_path
"$user",public
You can change your schema search path:
SET search_path TO showfinder,public;
See also http://www.postgresql.org/docs/8.3/static/ddl-schemas.html
I had problems with this and this is the story (sad but true) :
If your table name is all lower case like : accounts
you can use: select * from AcCounTs and it will work fine
If your table name is all lower case like : accounts
The following will fail:
select * from "AcCounTs"
If your table name is mixed case like : Accounts
The following will fail:
select * from accounts
If your table name is mixed case like : Accounts
The following will work OK:
select * from "Accounts"
I dont like remembering useless stuff like this but you have to ;)
Postgres process query different from other RDMS. Put schema name in double quote before your table name like this, "SCHEMA_NAME"."SF_Bands"
Put the dbname parameter in your connection string. It works for me while everything else failed.
Also when doing the select, specify the your_schema.your_table like this:
select * from my_schema.your_table
If a table name contains underscores or upper case, you need to surround it in double-quotes.
SELECT * from "Table_Name";
I had a similar problem on OSX but tried to play around with double and single quotes. For your case, you could try something like this
$query = 'SELECT * FROM "sf_bands"'; // NOTE: double quotes on "sf_Bands"
This is realy helpfull
SET search_path TO schema,public;
I digged this issues more, and found out about how to set this "search_path" by defoult for a new user in current database.
Open DataBase Properties then open Sheet "Variables"
and simply add this variable for your user with actual value.
So now your user will get this schema_name by defoult and you could use tableName without schemaName.
You must write schema name and table name in qutotation mark. As below:
select * from "schemaName"."tableName";
I had the same issue as above and I am using PostgreSQL 10.5.
I tried everything as above but nothing seems to be working.
Then I closed the pgadmin and opened a session for the PSQL terminal.
Logged into the PSQL and connected to the database and schema respectively :
\c <DATABASE_NAME>;
set search_path to <SCHEMA_NAME>;
Then, restarted the pgadmin console and then I was able to work without issue in the query-tool of the pagadmin.
For me the problem was, that I had used a query to that particular table while Django was initialized. Of course it will then throw an error, because those tables did not exist. In my case, it was a get_or_create method within a admin.py file, that was executed whenever the software ran any kind of operation (in this case the migration). Hope that helps someone.
In addition to Bill Karwin's answer =>
Yes, you should surround the table name with double quotes. However, be aware that most probably php will not allow you to just write simply:
$query = "SELECT * FROM "SF_Bands"";
Instead, you should use single quotes while surrounding the query as sav said.
$query = 'SELECT * FROM "SF_Bands"';
You have to add the schema first e.g.
SELECT * FROM place.user_place;
If you don't want to add that in all queries then try this:
SET search_path TO place;
Now it will works:
SELECT * FROM user_place;
Easiest workaround is Just change the table name and all column names to lowercase and your issue will be resolved.
For example:
Change Table_Name to table_name and
Change ColumnName to columnname
It might be silly for a few, but in my case - once I created the table I could able to query the table on the same session, but if I relogin with new session table does not exits.
Then I used commit just after creating the table and now I could able to find and query the table in the new session as well. Like this:
select * from my_schema.my_tbl;
Hope this would help a few.
Make sure that Table name doesn't contain any trailing whitespaces
Try this: SCHEMA_NAME.TABLE_NAME
I'd suggest checking if you run the migrations or if the table exists in the database.
I tried every good answer ( upvote > 10) but not works.
I met this problem in pgAdmin4.
so my solution is quite simple:
find the target table / scheme.
mouse right click, and click: query-tool
in this new query tool window, you can run your SQL without specifying set search_path to <SCHEMA_NAME>;
you can see the result:

What is the TABLE keyword for in this CTE expression

in this I post came across this weird postgres query:
WITH max_i AS
( SELECT MAX(i) FROM test )
SELECT *
FROM test
WHERE i = (TABLE max_i) - 1 ;
It was able to use the CTE return value like a simple variable through the use of the TABLE keyword. I looked through the documentation of postgres, but I couldn't find any mention of what it is or what it is used for. Can someone explain to me how it works?
It's a short way of writing
select * from max_i
See the manual for details

Get all except built-in schema names from a specific database using T-SQL query

As the title entails, is this possible?
Using the following code returns a list of the built-in schemas as well as all the other schemas:
select name from MyDbName.sys.schemas
What I want is only the schemas I created for each table. I also tried doing the following code but its not very solid.
select name from MyDbName.sys.schemas where name not like '%db_%'
select distinct SCHEMA_NAME(schema_id) from sys.objects
I think this will work for you.

Create table with postgreSQL [duplicate]

I'm trying to run the following PHP script to do a simple database query:
$db_host = "localhost";
$db_name = "showfinder";
$username = "user";
$password = "password";
$dbconn = pg_connect("host=$db_host dbname=$db_name user=$username password=$password")
or die('Could not connect: ' . pg_last_error());
$query = 'SELECT * FROM sf_bands LIMIT 10';
$result = pg_query($query) or die('Query failed: ' . pg_last_error());
This produces the following error:
Query failed: ERROR: relation "sf_bands" does not exist
In all the examples I can find where someone gets an error stating the relation does not exist, it's because they use uppercase letters in their table name. My table name does not have uppercase letters. Is there a way to query my table without including the database name, i.e. showfinder.sf_bands?
From what I've read, this error means that you're not referencing the table name correctly. One common reason is that the table is defined with a mixed-case spelling, and you're trying to query it with all lower-case.
In other words, the following fails:
CREATE TABLE "SF_Bands" ( ... );
SELECT * FROM sf_bands; -- ERROR!
Use double-quotes to delimit identifiers so you can use the specific mixed-case spelling as the table is defined.
SELECT * FROM "SF_Bands";
Re your comment, you can add a schema to the "search_path" so that when you reference a table name without qualifying its schema, the query will match that table name by checked each schema in order. Just like PATH in the shell or include_path in PHP, etc. You can check your current schema search path:
SHOW search_path
"$user",public
You can change your schema search path:
SET search_path TO showfinder,public;
See also http://www.postgresql.org/docs/8.3/static/ddl-schemas.html
I had problems with this and this is the story (sad but true) :
If your table name is all lower case like : accounts
you can use: select * from AcCounTs and it will work fine
If your table name is all lower case like : accounts
The following will fail:
select * from "AcCounTs"
If your table name is mixed case like : Accounts
The following will fail:
select * from accounts
If your table name is mixed case like : Accounts
The following will work OK:
select * from "Accounts"
I dont like remembering useless stuff like this but you have to ;)
Postgres process query different from other RDMS. Put schema name in double quote before your table name like this, "SCHEMA_NAME"."SF_Bands"
Put the dbname parameter in your connection string. It works for me while everything else failed.
Also when doing the select, specify the your_schema.your_table like this:
select * from my_schema.your_table
If a table name contains underscores or upper case, you need to surround it in double-quotes.
SELECT * from "Table_Name";
I had a similar problem on OSX but tried to play around with double and single quotes. For your case, you could try something like this
$query = 'SELECT * FROM "sf_bands"'; // NOTE: double quotes on "sf_Bands"
This is realy helpfull
SET search_path TO schema,public;
I digged this issues more, and found out about how to set this "search_path" by defoult for a new user in current database.
Open DataBase Properties then open Sheet "Variables"
and simply add this variable for your user with actual value.
So now your user will get this schema_name by defoult and you could use tableName without schemaName.
You must write schema name and table name in qutotation mark. As below:
select * from "schemaName"."tableName";
I had the same issue as above and I am using PostgreSQL 10.5.
I tried everything as above but nothing seems to be working.
Then I closed the pgadmin and opened a session for the PSQL terminal.
Logged into the PSQL and connected to the database and schema respectively :
\c <DATABASE_NAME>;
set search_path to <SCHEMA_NAME>;
Then, restarted the pgadmin console and then I was able to work without issue in the query-tool of the pagadmin.
For me the problem was, that I had used a query to that particular table while Django was initialized. Of course it will then throw an error, because those tables did not exist. In my case, it was a get_or_create method within a admin.py file, that was executed whenever the software ran any kind of operation (in this case the migration). Hope that helps someone.
In addition to Bill Karwin's answer =>
Yes, you should surround the table name with double quotes. However, be aware that most probably php will not allow you to just write simply:
$query = "SELECT * FROM "SF_Bands"";
Instead, you should use single quotes while surrounding the query as sav said.
$query = 'SELECT * FROM "SF_Bands"';
You have to add the schema first e.g.
SELECT * FROM place.user_place;
If you don't want to add that in all queries then try this:
SET search_path TO place;
Now it will works:
SELECT * FROM user_place;
Easiest workaround is Just change the table name and all column names to lowercase and your issue will be resolved.
For example:
Change Table_Name to table_name and
Change ColumnName to columnname
It might be silly for a few, but in my case - once I created the table I could able to query the table on the same session, but if I relogin with new session table does not exits.
Then I used commit just after creating the table and now I could able to find and query the table in the new session as well. Like this:
select * from my_schema.my_tbl;
Hope this would help a few.
Make sure that Table name doesn't contain any trailing whitespaces
Try this: SCHEMA_NAME.TABLE_NAME
I'd suggest checking if you run the migrations or if the table exists in the database.
I tried every good answer ( upvote > 10) but not works.
I met this problem in pgAdmin4.
so my solution is quite simple:
find the target table / scheme.
mouse right click, and click: query-tool
in this new query tool window, you can run your SQL without specifying set search_path to <SCHEMA_NAME>;
you can see the result:

SQLite query in Objective C iPhone App

I am building this application which fetches data from SQLite database tables, when a string is being entered in to UISearchBar, all possible entries should be printed. Right now i am able to fetch all the entries from the table but i am not able to perform the specific search, can anyone help me with the query or give some example to refer?
SELECT * FROM mytable WHERE myfield like '%your searchwordhere%' by executing this query you can get the words which are having the word of your search keyword.
Try this:
SELECT fieldone, fieldtwo FROM mytable WHERE myfield like '%%SEARCH_TERM_GOES_HERE%%'