concat

问题 In MySQL, I need to rename a table with a suffix which identifies previous month, and I'm trying to do that with this syntax: RENAME TABLE 'myTable' TO CONCAT('myTable',DATE_FORMAT(CURRENT_DATE - INTERVAL 1 MONTH, '%Y_%m')); F.e: I've table name "customers" and what I want is "customer_2015_04". The problem is with concat order. What am I doing wrong? Best regards, 回答1: I think you need to do this using a prepared statement: set @sql = CONCAT('RENAME TABLE myTable TO myTable', DATE_FORMAT

问题 I have two data frames and I am just writing a simple pd.concat to append the data vertically: SRC_OF_PAYMENT_80_00_CY= pd.concat(['src_of_payment_cy','src_of_payment_df'],axis=0, ignore_index=True) Both are dataframes types. So I don't understand the error: TypeError: cannot concatenate a non-NDFrame object Here is the out for df.info() for both: <class 'pandas.core.frame.DataFrame'> Int64Index: 10 entries, 0 to 9 Data columns (total 3 columns): Type_of_cost 10 non-null object Total_NHE 10

问题 I have different databases. I have tables within each database. I would like to know if I can ask how many databases excluding some such as 'schema' 'mysql' I have once know how to perform a subquery asked by a particular table of all the databases resulting from the first question. example. the structure would be db1 -> user-> id,name,imei,telephone,etc.. db2 -> user-> id,nameuser,imei,telephone,etc.. db3 -> user-> id,nameuser,imei,telephone,etc.. .... db1000 -> user-> id,nameuser,imei

问题 I would like to merge two CSV files as follow: First CSV File : df = pd.DataFrame() df["ticket_number"] = ['AAA', 'AAA', 'AAA', 'ABC', 'ABA','ADC','ABA','BBB'] df["train_board_station"] = ['Tokyo', 'LA', 'Paris', 'New_York', 'Delhi','Phoenix', 'London','LA'] df["train_off_station"] = ['Phoenix', 'London', 'Sydney', 'Berlin', 'Shanghai','LA', 'Paris', 'New_York'] Second CSV file: rec = pd.DataFrame() rec["code"] = ['Tokyo','London','Paris','New_York','Shanghai','LA','Sydney','Berlin','Phoenix'

问题 I want to concat multiple(3) columns in oracle sql query. Currently I am using function concat . Someone suggested to use || in place of concat as it gives performance benefit. Is it true? If yes why? I see only benefit of || is that written query more readable. 回答1: I set up a simple PL/SQL script(below) to try both concatenation options within a loop 100 million times each. The result for || was 142.93 seconds and CONCAT was 144.11 seconds. Either way, you're talking about roughly 1.4

问题 I got a MySQL data Table, with a JSON Column containing a list of Values: CONSTRAINT_TABLE ID | CONSTRAINT_TYPE | CONSTRAINT_VALUES ----+-----------------+-------------------------------- '2'| 'testtype' |'[801, 751, 603, 753, 803]' ...| ... | ... What I want to have is a distinct, comma-seperated List of JSON-Values. I tried it with group_concat, but it applys to the arrays, not the single values. SELECT group_concat(distinct constraint_values->>'$') FROM constraint_table c WHERE c

问题 I'm using Teradata, I have a table like this ID String 123 Jim 123 John 123 Jane 321 Jill 321 Janine 321 Johan I want to query the table so I get ID String 123 Jim, John, Jane 321 Jill, Janine, Johan I tried partition but there can be many names. How do I get this result. Even, to point me in the right direction would be great. 回答1: Unfortunately there's no PIVOT in Teradata (only a TD_UNPIVOT in 14.10). If you got luck there's an aggregate UDF at your site to do a group concat (probably low

问题 I'm using the gulp-order module along with the event-streams module and gulp-concat to concatenate javascript files into a single dest file. The gulp-order plugin has worked great for me in other projects where I wanted to concatenate files from the stream in a distinct order. For some reason in this project it is not working properly, and the files in the public/angular/config directory are dispersed amongst the files I specify to concatenate last in the public/js directory. I think this may

问题 I have two dataframes that I would like to concatenate column-wise (axis=1) with an inner join. One of the dataframes has some duplicate indices, but the rows are not duplicates, and I don't want to lose the data from those : df1 = pd.DataFrame([{'a':1,'b':2},{'a':1,'b':3},{'a':2,'b':4}], columns = ['a','b']).set_index('a') df2 = pd.DataFrame([{'a':1,'c':5},{'a':2,'c':6}],columns = ['a','c']).set_index('a') >>> df1 b a 1 2 1 3 2 4 8 9 >>> df2 c a 1 5 2 6 The default concat behavior is to fill

问题 So I installed npm using npm install uglify-js I run a command which is: cat file1.js file2.js .. fileN.js | uglifyjs -o files.min.js and I get this error: WARN: ERROR: Unexpected token eof «undefined», expected punc «,» [-:630,15] /usr/local/lib/node_modules/uglify-js/lib/parse.js:199 throw new JS_Parse_Error(message, line, col, pos); ^ Error at new JS_Parse_Error (/usr/local/lib/node_modules/uglify-js/lib/parse.js:185:18) at js_error (/usr/local/lib/node_modules/uglify-js/lib/parse.js:199