multiple-tables

问题 I have a table of songs, some songs are album song, and some are singles... And I have a table of albums... Example: if the album ID is [null], it means the song is a single Songs Table: +--------+---------+-----------+----------------+---------+---------------+-------+--------+--------+------+-------+-------+----------+ | Row ID | Song ID | Album ID | Song Name | Band | Date Released | Genre | Lyrics | Lenght | Size | Plays | Likes | Dislikes | +--------+---------+-----------+---------------

问题 I know how to run RENAME TABLE onetable_test TO onetable; But is there a method to rename many tables with a pattern and don't write a lot of code like RENAME TABLE onetable_test TO onetable; RENAME TABLE twotable_test TO twitable; RENAME TABLE threetable_test TO threetable; ... I am using mysql. Thanks! 回答1: Use below stored procedure :: DELIMITER $$ CREATE PROCEDURE `Rename_Tables`() BEGIN DECLARE done INT DEFAULT FALSE; DECLARE tableName VARCHAR(50); DECLARE newTableName VARCHAR(70);

问题 I know how to run RENAME TABLE onetable_test TO onetable; But is there a method to rename many tables with a pattern and don't write a lot of code like RENAME TABLE onetable_test TO onetable; RENAME TABLE twotable_test TO twitable; RENAME TABLE threetable_test TO threetable; ... I am using mysql. Thanks! 回答1: Use below stored procedure :: DELIMITER $$ CREATE PROCEDURE `Rename_Tables`() BEGIN DECLARE done INT DEFAULT FALSE; DECLARE tableName VARCHAR(50); DECLARE newTableName VARCHAR(70);

问题 I have a 3 part problem thats been giving me trouble I know how to get the tables to work if I query 1 table at a time but I can't seem to figure out how I can combine both the tags and more_tags tables to get the same results. The 3 main problems I have are Listed below. PROBLEM 1 I want to be able to group the same tag from both the tags and more_tags tables. PROBLEM 2 I also want to be able to display the tags from each table that are not present in the other table. PROBLEM 3 I also want

问题 I have one BIG file (>10000 lines of data) and I want write out a separate file by ID. I have 50 unique ID names and I want a separate text file for each one. Here's what Ive got so far, and I keep getting errors. My ID is actually character string which I would prefer if I can name each file after that character string it would be best. for (i in 1:car$ID) { a <- data.frame(car[,i]) carib <- car1[,(c("x","y","time","sd"))] myfile <- gsub("( )", "", paste("C:/bridge", carib, "_", i, ".txt"))

问题 I'd really appreciate some help with an SQL query across tables. I realise this sort of thing is asked constantly, but I can't find a similar enough question to make sense of the answers. I want to select rows from table_A that have a corresponding tag in table_B . So, for example, " select rows from table_a which are tagged 'chair' " would return table_C . Also, id is a unique in table_a , and not in table_b . table_A: table_B: table_C: id object id tag id object 1 lamp 1 furniture 3 stool 2

问题 SELECT name, price, photo FROM drinks, drinks_photos WHERE drinks.id = drinks_id yeilds 5 rows (5 arrays), photo is the only unique field in a row. name, price get repeated ( here, fanta- name, price repeat 3 times. ) How do i get rid of these duplicates? Edit: I want name, price and all photo for each drink. id name price 1. fanta 5 2. dew 4 id photo drinks_id 1. ./images/fanta-1.jpg 1 2. ./images/fanta-2.jpg 1 3. ./images/fanta-3.jpg 1 4. ./images/dew-1.jpg 2 5. ./images/dew-2.jpg 2 回答1:

问题 I need help. I have 6 tabs on website. But when i`m clicking to one of the tab, all other tabs changes too. How i can to have unigue id for every tab ? Please help. This my codes: jQuery(document).ready(function () { // When user clicks on tab, this code will be executed jQuery("#tabs li").click(function () { // First remove class "active" from currently active tab jQuery("#tabs li").removeClass('active'); // Now add class "active" to the selected/clicked tab jQuery(this).addClass("active");

问题 Just started playing with Ruby (no IT background) and until now went it quite well. But since two days I'm stuck and don't understand what's going wrong... so many thanks already for helping me out with this problem!! The situation is as described below: I created a currencymaster table with the following columns: currmasdesc:string , currmasiso:string . I created a currencyrate table with the following columns: currratemasteridd:integer , currratemasteridc:integer , currraterate:decimal ,

问题 Database one is called widgets, it has "id" and "title". Database two is called widget-layouts and it has "module-id", "widget-id", "position", and "weight". What I am trying to do is check to see if widgets.id exists in widget-layout.widget-id and if it does, then does widget-layouts.position = 0. I also want to get the values of widgets that don't exist in widget-layouts. Here is the mysql query I have been working with. SELECT * FROM widgets, widget-layouts WHERE (widge-layouts.position =