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I'm running DBI in Perl and can't figure out how, when I run a prepared statement, I can figure out if the returned row count is 0.
I realize I can set a counter inside my while loop where I fetch my rows, but I was hoping there was a less ugly way to do it.
279
If you need a quick way to count rows that contain data, select all the cells in the first column of that data (it may not be column A). Just click the column header. The status bar, in the lower-right corner of your Excel window, will tell you the row count.
In SQL, you can make a database query and use the COUNT function to get the number of rows for a particular group in the table. Here is the basic syntax: SELECT COUNT(column_name) FROM table_name; COUNT(column_name) will not include NULL values as part of the count.
This can be achieved by using the following query. SELECT table_schema, SUM(row_count) AS total_rows FROM ( SELECT table_schema, count_rows_of_table(table_schema, table_name) AS row_count FROM information_schema.
MySQL COUNT() Function The COUNT() function returns the number of records returned by a select query.
The "caveat" in the documentation (linked to in a comment on another answer) is important, and provides the real, correct answer:
Generally, you can only rely on a row count after a non-SELECT execute (for some specific operations like UPDATE and DELETE), or after fetching all the rows of a SELECT statement.
For SELECT statements, it is generally not possible to know how many rows will be returned except by fetching them all. Some drivers will return the number of rows the application has fetched so far, but others may return -1 until all rows have been fetched. So use of the rows method or $DBI::rows with SELECT statements is not recommended.
85
Based on a quick look here, it seems that after you run
$statement->execute($arg)
you can access the row count via
$statement->rows
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