I want to parse a field with the following type of value:
"DAVE EBERT CONSTRUCTION~139 LENNOX STREET~SANTA CRUZ, CA 95060~~Business Phone Number:(831) 818-3170"
I would like to do a query like:
Update mytable set street = string_to_array(myfield,'~')[2]
But string_to_array does not "return" an array so it can't be chained in this way. However, it does return an array that can be used by other functions that take arrays like array_upper() so I don't know why it would not work.
My workaround is to create an array field and do this:
Update mytable set myfield_array = string_to_array(myfield,'~')
Update mytable set street = myfield_array[2]
Is there a more direct way to do this? But again, if I am extracting a lot of different array elements, maybe the less direct way performs better because you are converting string to array only once?
Try...
Update mytable set street = (string_to_array(myfield,'~'))[2]
You just need those parenthesis.
Use some extra ():
Update mytable set street = (string_to_array(myfield,'~'))[2]
Related
I have model I created on the fly for peewee. Something like this:
class TestTable(PeeweeBaseModel):
whencreated_dt = DateTimeField(null=True)
whenchanged = CharField(max_length=50, null=True)
I load data from a text file to a table using peewee, the column "whenchanged" contains all dates in a format of '%Y-%m-%d %H:%M:%S' as varchar column. Now I want to convert the text field "whenchanged" into a datetime format in "whencreated_dt".
I tried several things... I ended up with this:
# Initialize table to TestTable
to_execute = "table.update({table.%s : datetime.strptime(table.%s, '%%Y-%%m-%%d %%H:%%M:%%S')}).execute()" % ('whencreated_dt', 'whencreated')
which fails with a "TypeError: strptime() argument 1 must be str, not CharField": I'm trying to convert "whencreated" to datetime and then assign it to "whencreated_dt".
I tried a variation... following e.g. works without a hitch:
# Initialize table to TestTable
to_execute = "table.update({table.%s : datetime.now()}).execute()" % (self.name)
exec(to_execute)
But this is of course just the current datetime, and not another field.
Anyone knows a solution to this?
Edit... I did find a workaround eventually... but I'm still looking for a better solution... The workaround:
all_objects = table.select()
for o in all_objects:
datetime_str = getattr( o, 'whencreated' )
setattr(o, 'whencreated_dt', datetime.strptime(datetime_str, '%Y-%m-%d %H:%M:%S'))
o.save()
Loop over all rows in the table, get the "whencreated". Convert "whencreated" to a datetime, put it in "whencreated_dt", and save each row.
Regards,
Sven
Your example:
to_execute = "table.update({table.%s : datetime.strptime(table.%s, '%%Y-%%m-%%d %%H:%%M:%%S')}).execute()" % ('whencreated_dt', 'whencreated')
Will not work. Why? Because datetime.strptime is a Python function and operates in Python. An UPDATE query works in database-land. How the hell is the database going to magically pass row values into "datetime.strptime"? How would the db even know how to call such a function?
Instead you need to use a SQL function -- a function that is executed by the database. For example, Postgres:
TestTable.update(whencreated_dt=whenchanged.cast('timestamp')).execute()
This is the equivalent SQL:
UPDATE test_table SET whencreated_dt = CAST(whenchanged AS timestamp);
That should populate the column for you using the correct data type. For other databases, consult their manuals. Note that SQLite does not have a dedicated date/time data type, and the datetime functionality uses strings in the Y-m-d H:M:S format.
I have an nvarchar field in my database called CatCustom which contains comma-separated 5-character codes. It can contain as little as one code, or as many as 20 codes, separated by commas.
Right now, I use this query to add a new 5-character code to the field in given records (in this case the new code is LRR01):
UPDATE dbo.Sources
SET CatCustom = CONCAT_WS(', ', RTRIM(CatCustom), 'LRR01')
WHERE SourceID IN (1,2,3,4,5,8,9,44,63,45,101,102,222,344)
I need to add to this though: I need the record to be updated only if that 5-character code doesn't already exist somewhere in the CatCustom field, to ensure that code is not in there more than once.
How would I accomplish this?
EDIT: I really don't understand how this can be considered a duplicate of the suggested thread. This is a VERY specific case and has nothing to do with creating stored procedures and or variables. The alleged duplicated thread does not really help me - sorry.
Use STRING_SPLIT function to split the comma separated list and then add Not Exist condition in the WHERE clause like below
UPDATE dbo.Sources
SET CatCustom = CONCAT_WS(', ', RTRIM(CatCustom), 'LRR01')
WHERE SourceID IN (1,2,3,4,5,8,9,44,63,45,101,102,222,344)
AND NOT EXISTS (SELECT 1 FROM STRING_SPLIT(CatCustom, ',') where value = 'LRR01')
UPDATE dbo.Sources
SET
CatCustom = CONCAT_WS(', ', RTRIM(CatCustom), 'LRR01')
WHERE
SourceID IN (1,2,3,4,5,8,9,44,63,45,101,102,222,344)
AND CatCustom NOT LIKE '%LRR01%';
I am trying to remove entries from an array field that are found in a query.
tablename.listfield::integer[] has a full list
I am trying to remove a list of values from that field, which are gathered within the update query.
the ARRAY_REMOVE method only accepts single values, and the intarray module which has int[] - int[] doesn't seem to be an option.
the ARRAY[] && ARRAY[] can boolean return if there is overlap, but that doesn't help me
basically what I need is a real working version of this concept, which I know does not work.
UDPATE tablename SET listfield = ARRAY_REMOVE( listfield, ( select id from othertable ) )
is it possible to get this done with maybe a tricky CTE setup or something?
thanks!
I'm not sure why you say intarray doesn't seem to be an option, because it works just fine:
... SET listfield = listfield - ( SELECT array_agg(id) FROM othertable )
But if you want to do this without installing the extension, you can UNNEST the array and use the EXCEPT construct:
... SET listfield = ARRAY(SELECT UNNEST(listfield) EXCEPT SELECT id FROM othertable)
SQL - How can I return a value from a different table base on a parameter
First time poster, long time reader:
I am using a custom Excel function that allows be to pass parameters and build a SQL string that returns a value. This is working fine. However, I would like to choose among various tables based on the parameters that are passed.
At the moment I have two working functions with SQL statements look like this:
_______FUNCTION ONE________
<SQLText>
SELECT PRODDTA.TABLE1.T1DESC as DESCRIPTION
FROM PRODDTA.TABLE1
WHERE PRODDTA.TABLE1.T1KEY = '&PARM02'</SQLText>
_______FUNCTION TWO________
<SQLText>
SELECT PRODDTA.TABLE2.T2DESC as DESCRIPTION
FROM PRODDTA.TABLE2
WHERE PRODDTA.TABLE2.T2KEY = '&PARM02'</SQLText>
So I am using IF logic in Excel to check the first parameter and decide which function to use.
It would be much better if I could do a single SQL statement that could pick the right table based on the 1st parameter. Logically something like this:
_______FUNCTIONS COMBINED________
IF '&PARM02' = “A” THEN
SELECT PRODDTA.TABLE1.T1DESC as DESCRIPTION
FROM PRODDTA.TABLE1
WHERE PRODDTA.TABLE1.T1KEY = '&PARM02'
ELSE IF '&PARM02' = “B” THEN
SELECT PRODDTA.TABLE2.T2DESC as DESCRIPTION
FROM PRODDTA.TABLE2
WHERE PRODDTA.TABLE2.T2KEY = '&PARM02'
ELSE
DESCRIPTION = “”
Based on another post Querying different table based on a parameter I tried this exact syntax with no success
<SQLText>
IF'&PARM02'= "A"
BEGIN
SELECT PRODDTA.F0101.ABALPH as DESCRIPTION
FROM PRODDTA.F0101
WHERE PRODDTA.F0101.ABAN8 = '&PARM02'
END ELSE
BEGIN
SELECT PRODDTA.F4801.WADL01 as DESCRIPTION
FROM PRODDTA.F4801
WHERE PRODDTA.F4801.WADOCO = '&PARM02'
END</SQLText>
You could try using a JOIN statement.
http://www.sqlfiddle.com/#!9/23461d/1
Here is a fiddle showing two tables.
The following code snip will give you the values from both tables, using the Key as the matching logic.
SELECT Table1.description, Table1.key, Table2.description
from Table1
Join Table2 on Table1.key = Table2.key
Here's one way to do it. If PARM03='Use Table1' then the top half of the union will return records and vice versa. This won't necessarily product good performance though. You should consider why you are storing data in this way. It looks like you are partitioning data across different tables which is a bad idea.
SELECT PRODDTA.TABLE1.T1DESC as DESCRIPTION
FROM PRODDTA.TABLE1
WHERE PRODDTA.TABLE1.T1KEY = '&PARM02'
AND &PARM03='Use Table1'
UNION ALL
SELECT PRODDTA.TABLE2.T2DESC as DESCRIPTION
FROM PRODDTA.TABLE2
WHERE PRODDTA.TABLE2.T2KEY = '&PARM02'</SQLText>
AND &PARM03='Use Table2'
I know how to update a record and replace a sub string in another string:
update(conn,'tableName',{'columnName'},{'value'},'where columName=xx') %update record in database
modifiedStr = strrep(origStr, oldSubstr, newSubstr) %replaces substring with new string in another string.
Now i want to mix these two and change substring of a record in the database. How can we do that? I want a query to do this. Can we mix the two by any chance?
You don't need the {} brackets if you deal with only one column.
If you have a the column name and hold it in a variable columnName, you can try something similar:
columnName = 'product_id';
whereClause = ['where ',columName,'=',origStr];
modifiedStr = strrep(origStr, oldSubstr, newSubstr);
update(conn,'tableName',columnName,modifiedStr,whereClause);
Of course you don't need to use the variables you can just replace the desired string inside the update function, but I did it for clarification.