I'm trying to quickly insert large number of rows into the following table:
CREATE TABLE word
(word_id int(10) PRIMARY KEY AUTO_INCREMENT ,
word_txt VARCHAR(40) NOT NULL UNIQUE)
using executemany() :
query = "INSERT IGNORE INTO word (word_txt) VALUES (%s)"
try:
self.cursor.executemany(query,word_list)
except ...
word_list is a list of single string tuples.
e.g: word_list = [('cases',), ('regard',), ('disregard',), ...]
Interface Error returns at execution: "No result set to fetch from".
using an alternative:
query = f"INSERT IGNORE INTO word (word_txt) VALUES {words}"
try:
self.cursor.execute(query)
except
according to MySQL the syntax is invalid after execution.
same as before words is a list of of single string tuples.
the value of (string) variable "query" at the moment of debugging:
query = INSERT IGNORE INTO word (word_txt) VALUES [('tire',), ('object',), ('really',), ...,('these',), ('regarded',)]
Would appreciate any help.
Related
I'm trying to update my table column values into a string. My query goes like this
UPDATE tbl_testing
SET result= 'Hey'
WHERE (SELECT (colOne) + '-' + (colTwo) + '-' + (colThree)) = 'r-r-r'
which the columns 'colOne, colTwo and colThree' already contains 'r' but slqyog shows "Truncated incorrect DOUBLE value: 'r-r-r'"
and all of the other result column data became = 'Hey'. What should I do?
You have to decide it is either MySQL or MSSQL.
In MySQL the string concatenation is not + sign, but simply you enumerate the columns separated by comma and the statement is SELECT CONCAT("Field1", "Field2" etc) AS ConcatenatedString); - CONCAT() function.
Try reevaluate your DB engine and adapt the query.
In MSSQL the string concatenation is indeed + sign. Your query works ok in MSSQL and updates the result column with the value you have set.
DDL
CREATE TABLE [dbo].[tbl_testing](
[id] [int] NULL,
[result] [nvarchar](4000) NULL,
[colOne] [nvarchar](4000) NULL,
[colTwo] [nvarchar](4000) NULL,
[colThree] [nvarchar](4000) NULL
) ON [PRIMARY]
GO
INSERT INTO tbl_testing (id, colOne, colTwo, colThree)
VALUES (1, 'r', 'r', 'r')
Update statement
UPDATE tbl_testing
SET result='Hey. I am a concatenated string'
WHERE (SELECT (colOne)+'-'+(colTwo)+'-'+(colThree))='r-r-r'
Output
id result colOne colTwo colThree
1 Hey. I am a concatenated string r r r
Changing comment to answer:
You should avoid doing that statements in that way. By doing that, database use no indexes and also you are giving more computation tasks to database server (server needs to concatenate all values and after concatenations will compare with given string).
Better way is to replace yours where statement with something like:
`WHERE colOne = 'r' AND colTwo = 'r' AND ...`
that will work faster without additional computation need (to concatenate strings).
This solution works much much faster, and looks much much better.
I have a MySQL database table that contains column run that is an integer and another column filename that is a varchar with typical values like RUN0001.FTS or 3DS0231.FTS or 3RUN0010.FTS
I need to check the values in the run and filename columns. The prescription is I extract the last integer (without leading zeroes) before the dot character (.) in the filename column, and compare it to the value of the run column. How do I write a select statement to do this comparison to return the rows that will not have the matching integers?
For example, a regular expression I am trying to build would extract 1 from RUN0001.FTS, or 231 from 3DS0231.FTS, or 10 from 3RUN0010.FTS and then compare it to the value in the run column, and return the primary key if the two don't match.
In Python I would manipulate the variable filename = '3RUN0010.FTS' like so:
import re
filename = '3RUN0010.FTS'
fileRunNumber = re.findall('\d+', filename)
runNumber = int(fileRunNumber[-1])
print "The integer I want is", runNumber
How do I do this in as a MySQL statement?
Thanks,
Aina.
You can try the following query:
SELECT CAST(SUBSTRING(col, INSTR(col, '.') - 4, 4) AS UNSIGNED) AS theNumber
FROM yourTable
Data:
CREATE TABLE yourTable (col varchar(55));
INSERT INTO yourTable (col)
VALUES
('RUN0001.FTS'),
('3DS0231.FTS'),
('3RUN0010.FTS');
Output:
Demo here:
Rextester
Now I use to manually parse json into insert string like so
insert into Table (field1, field2) values (val1, val2)
but its not comfortable way to insert data from json!
I've found function json_populate_record and tried to use it:
create table test (id serial, name varchar(50));
insert into test select * from json_populate_record(NULL::test, '{"name": "John"}');
but it fails with the message: null value in column "id" violates not-null constraint
PG knows that id is serial but pretends to be a fool. Same it do for all fieds with defaults.
Is there more elegant vay to insert data from json into a table?
There's no easy way for json_populate_record to return a marker that means "generate this value".
PostgreSQL does not allow you to insert NULL to specify that a value should be generated. If you ask for NULL Pg expects to mean NULL and doesn't want to second-guess you. Additionally it's perfectly OK to have a generated column that has no NOT NULL constraint, in which case it's perfectly fine to insert NULL into it.
If you want to have PostgreSQL use the table default for a value there are two ways to do this:
Omit that row from the INSERT column-list; or
Explicitly write DEFAULT, which is only valid in a VALUES expression
Since you can't use VALUES(DEFAULT, ...) here, your only option is to omit the column from the INSERT column-list:
regress=# create table test (id serial primary key, name varchar(50));
CREATE TABLE
regress=# insert into test(name) select name from json_populate_record(NULL::test, '{"name": "John"}');
INSERT 0 1
Yes, this means you must list the columns. Twice, in fact, once in the SELECT list and once in the INSERT column-list.
To avoid the need for that this PostgreSQL would need to have a way of specifying DEFAULT as a value for a record, so json_populate_record could return DEFAULT instead of NULL for columns that aren't defined. That might not be what you intended for all columns and would lead to the question of how DEFAULT would be treated when json_populate_record was not being used in an INSERT expression.
So I guess json_populate_record might be less useful than you hoped for rows with generated keys.
Continuing from Craig's answer, you probably need to write some sort of stored procedure to perform the necessary dynamic SQL, like as follows:
CREATE OR REPLACE FUNCTION jsoninsert(relname text, reljson text)
RETURNS record AS
$BODY$DECLARE
ret RECORD;
inputstring text;
BEGIN
SELECT string_agg(quote_ident(key),',') INTO inputstring
FROM json_object_keys(reljson::json) AS X (key);
EXECUTE 'INSERT INTO '|| quote_ident(relname)
|| '(' || inputstring || ') SELECT ' || inputstring
|| ' FROM json_populate_record( NULL::' || quote_ident(relname) || ' , json_in($1)) RETURNING *'
INTO ret USING reljson::cstring;
RETURN ret;
END;
$BODY$
LANGUAGE plpgsql VOLATILE;
Which you'd then call with
SELECT jsoninsert('test', '{"name": "John"}');
I have a table:
CREATE TABLE `ids` (
id int(11) not null auto_increment,
PRIMARY KEY (id)
);
It contains some IDs: 111, 112, 113, 114 etc.
I made a query:
SELECT * FROM `ids` WHERE id = '112abcdefg'
I expected nothing but I've got a result, a row with ID of 112. Seems that MySQL quietly converted my string to integer and then compared it against column values.
How can I change the query so that querying the same string from id column will give no results as I expect? Is there a strict comparison modifier in MySQL?
One option is to CAST the 112 to CHAR to get a proper match:
WHERE CAST(id AS CHAR(12)) = '112abcdefg'
The 12 in CHAR is a guess; it should be large enough for your biggest id.
That will probably kill any chance of optimization, so another option (though one I'm not 100% sure of) is to use a BINARY comparison. I've tried this with a few different values and it works:
WHERE BINARY id = '112abcdefg'
You are comparing a string, just put the number with no quotes:
SELECT * FROM `ids` WHERE id = 112
If you dont, it will convert the string '112abcdefg' to a number and say its 112
The response you are seeing is because you are trying to compare an integer column to a string value. In that case, MySQL will type-cast the string literal value to an integer, and when it does that it starts from the left of the string and as soon as it reaches a character that cannot be considered part of a number, it strips out everything from that point on. So trying to compare "256abcd" to an integer column will result in actually comparing the number 256.
So your options (or at least a few of them) would be:
Validate the input string in your application code and reject it if it's not an integer (see the ctype_digit function in PHP).
Change the column type for the filename if you want to treat it as a string (e.g. a VARCHAR type).
Cast the column value to a string:
. . . WHERE CAST(Id AS CHAR) = '256aei'
Source
you can use this :
SET sql_mode = STRICT_TRANS_TABLES;
this sets you sql mode to strict checking, and then try firing the query you mentioned.
lame + kills optimization but serves it purpose
SELECT * FROM `ids` WHERE concat(id) = '112abcdefg';
that way you enforce casting to string
http://dev.mysql.com/doc/refman/5.1/en/type-conversion.html
i have a database i insert item into using php. i want to get the ID which is auto increment column, i read the manual and it says that the mysql_query returns a resource variable rather than boolean, is there any way to retreive data from that resouce?
echo $query_ins = "INSERT INTO `house` VALUES ('' , '$city', '$street', 'num');
$res = mysql_query($query_ins);
the first field is the ID field i am interested in.
i tried mysql_fetch_assoc and mysql_result function to convert the $res into array or retrieve data directly like i would do with SELECT query but no succes.
any suggestions?
See the manual: mysql_insert_id — Get the ID generated in the last query
This is really something you should have been able to find on your own easily, without posting to StackOverflow. It's to your advantage to review the documentation of any API you're using.
Re your comment:
SELECT * FROM house WHERE id = LAST_INSERT_ID()
This supposes you have an auto-incrementing primary key.
If you generate a nondeterministic primary key value on insert, for example using RAND() or UUID(), then there is effectively no way to retrieve the value generated. You should generate the value before doing the INSERT, so you have a literal value you can use to look up the row.
SET #r := RAND();
INSERT INTO house (id, ...) VALUES (#r, ...);
SELECT * FROM house WHERE id = #r;
MD5 is deterministic, so supposing you have an original key string that you hash, you should be able to retrieve the row using that MD5 expression and the original string.
INSERT INTO house (id, ...) VALUES (MD5('xyzzy'), ...);
SELECT * FROM house WHERE id = MD5('xyzzy');