mysql, iterate through column names
I would like to get all of the column names from a MySQL table, loop through each column name and then run a开发者_JAVA百科 stored procedure using those column names as a variable. Something to the effect of:
colnames = get column names from table
for each colname
if something changed then
do something
else
do something else
It looks like SHOW COLUMNS FROM myTable
will give me the column names, but how would I get the column names into a loop?
I would really like to run all of this in a stored procedure using native SQL. Since I'm still learning the intricacies of MySQL, and this would really help out my project. Thanks for your help.
I think you want something like this:
DECLARE col_names CURSOR FOR
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'tbl_name'
ORDER BY ordinal_position;
select FOUND_ROWS() into num_rows;
SET i = 1;
the_loop: LOOP
IF i > num_rows THEN
CLOSE col_names;
LEAVE the_loop;
END IF;
FETCH col_names
INTO col_name;
//do whatever else you need to do with the col name
SET i = i + 1;
END LOOP the_loop;
You can write a query against information_schema to get the column names:
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'tbl_name'
ORDER BY ordinal_position
The column names are then returned just as any data from a table would be.
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