I have a database with a Table named PaymentReciept I was playing around and found some unexpected results from a simple select all query.
// Return 3139 rows
select * from PaymentReciept
// Return 3139 rows
select * from dbo.PaymentReciept
// Return 0 rows
select * from [dbo.PaymentReciept]
I don't understand why the query with square brackets return no results. I know that square brackets are used as delimiters for identifiers that use some special character or a keyword.
Can someone kindly explain to me what's going on or direct me to some article or a book where I can learn more about this behavior.
[dbo.PaymentReciept]
Means that SQL is querying a table whose name is dbo.PaymentReceipt
whereas
dbo.PaymentReciept and PaymentReciept means that SQL is querying a table called PaymentReceipt in the schema dbo.
To use square brackets correctly, use:
[dbo].[PaymentReciept]
Square brackets should be placed around schema name (dbo) and the table name (PaymentReciept), as these two are separate objects:
select * from [dbo].[PaymentReciept]
Related
I have a table named Posts I would like to count and profile in Snowflake using the current Snowsight UI.
When I return the results via EXPLAIN using TABLULAR I am able to return the set with the combination of TABLE, RESULT_SCAN, and LAST_QUERY_ID functions, but any predicate or filter or column reference seems to fail.
Is there a valid way to do this in Snowflake with the TABLE function or is there another way to query the output of the EXPLAIN using TABLULAR?
-- Works
EXPLAIN using TABULAR SELECT COUNT(*) from Posts;
-- Works
SELECT t.* FROM TABLE(RESULT_SCAN(LAST_QUERY_ID())) as t;
-- Does not work
SELECT t.* FROM TABLE(RESULT_SCAN(LAST_QUERY_ID())) as t where operation = 'GlobalStats';
-- invalid identifier 'OPERATION', the column does not seem recognized.
Tried the third example and expected the predicate to apply to the function output. I don't understand why the filter works on some TABLE() results and not others.
You need to double quote the column name
where "operation"=
From the Documentation
Note that because the output column names from the DESC USER command
were generated in lowercase, the commands use delimited identifier
notation (double quotes) around the column names in the query to
ensure that the column names in the query match the column names in
the output that was scanned
Is square bracket in table name, column name or datatype is not supported in postgresql ?
I am getting below error while running the query in pgadmin:
CREATE TABLE [Test];
ERROR: syntax error at or near "["
SQL state: 42601
In PostgreSQL you can use double quotes :
CREATE TABLE "Test";
Same for columns, square brackets are used in SQL-Server.
If you mean the table name would be [Test] with brackets included then you would use "[Test]".
Create table "[Test]" ...;
If you meant it as an identifier, you could simply use without brackets or double quotes as Test.
Create table Test ...;
This way, you could refer to it as Test or test or tESt without double quotes in subsequent queries, ie:
select * from test;
If you use "Test" then postgreSQL would treat it as case sensitive and you would always use "Test".
Create table "Test" ...;
If you were trying to emphasize the identifier name by using square brackets, then sagi's answer is correct. On the other hand, if you really want to use square brackets in your table name, postgresql supports this as "[Test]". In this case your table name will include square brackets. You can get additional info from postgresql documentation
I have a table called project-users and want to write a SQL query like SELECT * FROM project-users I get this error ERROR: syntax error at or near "-".
I cannot change the table name at this point.
According to http://www.postgresql.org/docs/9.0/static/sql-syntax-lexical.html, you should use double quotes.
In your case, for PostgreSQL the query should be:
SELECT * FROM "project-users";
It is good practice to avoid the use of characters that need escaping or that contain spaces in identifiers.
I made a mistake and entered:
SELECT * FROM table LIMIT1
instead of
SELECT * FROM table LIMIT 1 (note the space between LIMIT and 1)
in the CLI of MySQL. I expected to receive some kind of parse error, but I was surprised, because the query returned all of the records in the table. My first thought was "stupid MySQL, I bet that this will return error in PostgreSQL", but PostgreSQL also returned all records. Then tested it with SQLite - with the same result.
After some digging, I realized that it doesn't matter what I enter after the table. As long as there are no WHERE/ORDER/GROUP clauses:
SELECT * FROM table SOMETHING -- works and returns all records in table
SELECT * FROM table WHERE true SOMETHING -- doesn't work - returns parse error
I guess that this is a standardized behavior, but I couldn't find any explanation why's that. Any ideas?
Your first query is equivalent to this query using a table alias:
SELECT * FROM yourtable AS LIMIT1
The AS keyword is optional. The table alias allows you to refer to columns of that table using the alias LIMIT1.foo rather than the original table name. It can be useful to use aliases if you wish to give tables a shorter or a more descriptive alias within a query. It is necessary to use aliases if you join a table to itself.
From the SQL lite documentation:
This is why I want DB engine to force the usage of keyword AS for alias names
http://beyondrelational.com/modules/2/blogs/70/posts/10814/should-alias-names-be-preceded-by-as.aspx
SELECT * FROM table LIMIT1;
LIMIT1 This has taken as alias by SQL, cause LIMIT1 is not a reserved literal of SQL.
Something after table name and that is not a reserved keyword always taken as an table alias by SQL.
SELECT * FROM table LIMIT 1;
When you used LIMIT just after the table name, SQL found that as a reserved keyword and worked for it as per the behavior. IF you want to use reserved key words in query It can be done by putting reserved literals in quotes. like..
SELECT * FROM table `LIMIT`;
OR
SELECT * FROM table `LIMIT 1`;
Now all words covered under `` quotes will treated as user defined.
Commonly we did mistake with date, timestamp, limit etc.. keywords by using them as column names.
I have this query:
select * from table where column like '%firstword[something]secondword[something]thirdword%'
What do I replace [something] with to match an unknown number of spaces?
Edited to add: % will not work as it matches any character, not just spaces.
Perhaps somewhat optimistically assuming "unknown number" includes zero.
select *
from table where
REPLACE(column_name,' ','') like '%firstwordsecondwordthirdword%'
The following may help: http://blogs.msdn.com/b/sqlclr/archive/2005/06/29/regex.aspx
as it describes using regular expressions in SQL queries in SQL Server 2005
I would definitely suggest cleaning the input data instead, but this example may work when you call it as a function from the SELECT statement. Note that this will potentially be very expensive.
http://www.bigresource.com/MS_SQL-Replacing-multiple-spaces-with-a-single-space-9llmmF81.html