I need to make a script that make a replacement of all the registers of a column that contains: '#xxxx', removing the single quotes. (xxxx could be empty or any string. The #, is neccesary, the simple quotes too).
I'm implementing something like this, but it doesn't work for me, because the 'REPLACE' function accepts Strings as parameters, instead of accepting other functions.
Thanks
I tried
UPDATE MY_TABLE SET MY_COLUMN = REPLACE('MY_COLUMN',
SELECT "MY_COLUMN" FROM MY_TABLE WHERE "MY_COLUMN" like '%''#%',
SELECT TRIM( '%''%' FROM MY_TABLE WHERE "MY_COLUMN" like '%''#%'))
Its unclear what dbms you are using, but here is what I would so in SQLServer, you can modify for you dbms if not this.
They key point here is you are doing this the wrong way round, you use the Replace function on each row, not pass the record set into the replace.
UPDATE mt
SET myColumn = REPLACE(myColumn, '''','')
FROM myTable mt
WHERE myColumn LIKE '%''#%'
Related
I have the following string:
SELECT hello as "helloHello", '' as "empty" FROM tbl_test
I want to do something like this:
INSERT INTO tbl_x (a, b, c) VALUES (x, y, string_from_above)
The strings are going to be dynamic (basically they're strings of sql statements), so I do not want to escape all the ' and ". If I open the postgres database and double click on the varchar column, I can copy and paste the string and it goes in exactly as it looks. I want to be able to programmatically do so. Is there a way using an insert command? I tried using pgFormat, but that didn't work. See attached pic with what it looks like in the table.
All PostgreSQL APIs worth their money have a way to escape strings for inclusion in a dynamic SQL statement.
For example, if you write in C, you can use libpq's PQescapeLiteral().
There are also SQL functions for this: quote_literal() and format(). They can be used in PL/pgSQL code.
Don't try to write your own code for this. Use prior art and avoid the risk of getting it wrong.
I am using PostgreSQL 11.9
I have a table containing a jsonb column with arbitrary number of key-values. There is a requirement when we perform a search to include all values from this column as well. Searching in jsonb is quite slow so my plan is to create a trigger which will extract all the values from the jsonb column:
select t.* from app.t1, jsonb_each(column_jsonb) as t(k,v)
with something like this. And then insert the values in a newly created column in the same table so I can use this column for faster searches.
My question is what type would be most suitable for storing the keys and then searchin within them. Currently the search looks like this:
CASE
WHEN something IS NOT NULL
THEN EXISTS(SELECT value FROM jsonb_each(column_jsonb) WHERE value::text ILIKE search_term)
END
where the search_term is what the user entered from the front end.
This is not going to be pretty, and normalizing the data model would be better.
You can define a function
CREATE FUNCTION jsonb_values_to_string(
j jsonb,
separator text DEFAULT ','
) RETURNS text LANGUAGE sql IMMUTABLE STRICT
AS 'SELECT string_agg(value->>0, $2) FROM jsonb_each($1)';
Then you can query like
WHERE jsonb_values_to_string(column_jsonb, '|') ILIKE 'search_term'
and you can define a trigram index on the left hand side expression to speed it up.
Make sure that you choose a separator that does not occur in the data or the pattern...
I have to produce a dynamically generated T-SQL script that inserts records into various tables. I've done a bunch of searching and testing but can't seem to find the path I'm looking for.
I know that the following is valid SQL:
INSERT INTO [MyTable] ( [Col1], [Col2], [Col3] )
SELECT N'Val1', N'Val2', N'Val3';
But, is it at all possible to write something akin to this:
INSERT INTO [MyTable]
SELECT [Col1] = N'Val1', [Col2] = N'Val2', [Col3] = N'Val3';
By having the columns in the select statement, I'm able to do it all at once vs writing 2 separate lines. Obviously my idea doesn't work, I'm trying to figure out whether something similar is possible or I need to stick with the first one.
Much appreciated.
Best practice for insert statements is to specify the columns list in the insert clause, and for very good reasons:
It's far more readable. You know exactly what value goes into what column.
You don't have to provide values to nullable \ default valued columns.
You're not bound to the order of the columns in the table.
In case a column is added to the table, your insert statement might not break (It will if the newly added column is not nullable and doesn't have a default value).
In some cases, SQL Server demands you specify the columns list explicitly, like when identity_insert is set to on.
And in any case, the column names or aliases in the select clause of the insert...select statement does not have any effect as to what target columns the value column should go to. values are directed to target based only on their location in the statement.
I would like to know how I can insert regular expression in a table column in a PostgreSQl table.
For example I have column called "rule" in a table where I need to store the expression ^[0-9]+$. I tried:
insert into rule_master(rule)
values('^[0-9]+$') where rule_id='7'
But I am getting error syntax near where is wrong. I tried this with and with out single quotes. Please suggest me a solution.
It appears you want to UPDATE an existing record. In that case you should do:
UPDATE rule_master
SET rule = '^[0-9]+$'
WHERE rule_id = '7';
But if this is indeed a new record and you want to INSERT that regex with the value of "rule_id" then do:
INSERT INTO rule_master(rule_id, rule)
VALUES ('7', '^[0-9]+$');
I want to select a column value and trim away a suffix matching a regular expression, all inside PostgreSQL, how can this be done?
-- somewhat like performing s/_bar$// on "foo_bar"
select regexp_replace('foo_bar', '_bar$', '')