Is there a way to import only one column in a single table from SQL dump file for MySQL?
Also is there a way to extract one table out using Unix command as the file I have is 18GB
What is the most efficient way to import only one column?
MyDumpSplitter is a tool that uses Linux commands like sed to extract one table from a larger SQL dump file.
However, extracting one column from that table is harder, since the INSERT statements contain full rows.
Probably the easiest solution is to restore the one table (for instance to the test database), and then SELECT the one column you want out of it.
Related
I was given an excel (csv) sheet containing a database metadata.
I'm asking if there's a simple way to import the csv and create the tables from there?
Data is not part of this question. the csv looks like this:
logical_table_name, physical_table_name, logical_column_name, physcial_column_name, data_type, data_length
There's about 2000 rows of metadata. I'm hoping I don't have to manually create the tables. Thanks.
I don't know of any direct import or creation. However, if I had to do this and I couldn't find one, I would import the excel file into a staging table (just a direct data import). I'd make add a unique auto ID column to staging table to keep the rows in order.
Then I would use some queries to build table and column creation commands from the raw data. Unless this was something I was setting up to do a lot, I would keep it dead simple, not try and get fancy. Build individual add column commands for each column. Build a create Table command for the first row for each table. Sort them all by the order id, tables before columns. Then you should be able to just copy the script column, check the commands, and go.
i need to import some data from very huge csv file which is about 1GB.
instead of importing all, i want to just import matched data, i think it will be more easy and faster than importing all data.
i need to search "Post Code District" column of CSV file, if it contains LS1 or LS2 or LS10, import matched data into tabel in SQL?
Misconception. You think that filtering a text file against a database table is going to be faster than just loading the entire file into the database.
I support there are extreme cases where this might be true. But, in general, the safest way to handle these types of situation is:
Import the file into a staging table.
Add indexes, as necessary to the staging table for performance.
Run a query to copy the data you want from the staging table.
I could phrase this a different way. In the time it would take you to figure out how to efficient combine information from the file and a database table, you could probably go through the above process 10-50 times.
Is there a way to import a csv into a SQL table, without having a previously-constructed table? I know how to import a csv into an existing table, but is there a way to create one from the csv?
You can do this using phpMyAdmin ,
(in this method csv file first row elements use as column names for the sql table)
1) select database
2) go to import tab and select csv file
3) ↓↓↓↓↓↓↓
4) after above steps new table will be created and if you want to change table names instead of having table1,table2
select table and go to operation tab :)
(phpMyAdmin 4.1.14)
I am no expert in MySQL but I don't believe there is such an import process. And there might not be in other database servers like Oracle, SQL Server, or PostgreSQL. In fact, it may not be a desirable automation as a table should be user defined and created to fit the database's relational model and for appropriate data types, indices, and keys.
Almost all SQL dialects require setting up the database table beforehand. If not, how would the system know beforehand you intended an integer or long number, a double or decimal number, a tinytext or longtext, which fields are to be indexed, or serve as primary key, and so on?
You might argue MS Access allows a CSV import with an optional table name. However, the ribbon wizard walks the user through setting up the field types, primary key, and table name. And going the non-wizard automation route, the DoCmd.TransferText method requires table name when using the acImportDelim argument.
So, your best process in MySQL may be LOAD DATA INFILE to run a bulk import of an external CSV into an existing table.
I have a table that has 7000 rows,
I added a new column to this table
The table has a mysql DateTime so.
When i updated the table to fill in this new table it updated the datetime,
I took an sql dump just before i did the update so now i need to use the sql dump to revert the datetime back (and only that column).
How do i do that?
There are a couple ways I can think of to do this off the top of my head.
First is to create another mysql database and load the dump into that database (make sure it's not going to load into the first database from a use commmand in the dump), and then use the data from that database to construct the update queries for the first.
The second, easier, more hackish way, is to open the dump in a text editor, pull out just that table, and find and replace to make update statements for just that column based on primary key instead of inserts. You'd need to be able to find and replace on patterns.
A third way would be to load the dump in an abstract sql tool letting it do the parsing for you, and write new queries from the data in the abstract syntax trees.
A fourth, again hackish, possibility, if this isn't a live system, is to rollback and re-perform the more recent transformations (only if they are simple).
Restore the dump to a second table. Select the ID and datetime from that table. Use those results to update the rows in the original table corresponding to the IDs you got.
As the title says: I've got a bunch of tab-separated text files containing data.
I know that if I use 'CREATE TABLE' statements to set up all the tables manually, I can then import them into the waiting tables, using 'load data' or 'mysqlimport'.
But is there any way in MySQL to create tables automatically based on the tab files? Seems like there ought to be. (I know that MySQL might have to guess the data type of each column, but you could specify that in the first row of the tab files.)
No, there isn't. You need to CREATE a TABLE first in any case.
Automatically creating tables and guessing field types is not part of the DBMS's job. That is a task best left to an external tool or application (That then creates the necessary CREATE statements).
If your willing to type the data types in the first row, why not type a proper CREATE TABLE statement.
Then you can export the excel data as a txt file and use
LOAD DATA INFILE 'path/file.txt' INTO TABLE your_table;