Is there a way to get the count of rows in all tables in a MySQL database without running a SELECT count() on each table?
Is there a way to get the count of rows in all tables in a MySQL database without running a SELECT count() on each table?
SELECT SUM(TABLE_ROWS)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = '{your_db}';
Note from the docs though: For InnoDB tables, the row count is only a rough estimate used in SQL optimization. You'll need to use COUNT(*) for exact counts (which is more expensive).
You can probably put something together with Tables table. I've never done it, but it looks like it has a column for TABLE_ROWS and one for TABLE NAME.
To get rows per table, you can use a query like this:
SELECT table_name, table_rows
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = '**YOUR SCHEMA**';
Simple way:
SELECT
TABLE_NAME, SUM(TABLE_ROWS)
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_SCHEMA = '{Your_DB}'
GROUP BY TABLE_NAME;
Result example:
+----------------+-----------------+
| TABLE_NAME | SUM(TABLE_ROWS) |
+----------------+-----------------+
| calls | 7533 |
| courses | 179 |
| course_modules | 298 |
| departments | 58 |
| faculties | 236 |
| modules | 169 |
| searches | 25423 |
| sections | 532 |
| universities | 57 |
| users | 10293 |
+----------------+-----------------+
This is how I count TABLES and ALL RECORDS using PHP:
$dtb = mysql_query("SHOW TABLES") or die (mysql_error());
$jmltbl = 0;
$jml_record = 0;
$jml_record = 0;
while ($row = mysql_fetch_array($dtb)) {
$sql1 = mysql_query("SELECT * FROM " . $row[0]);
$jml_record = mysql_num_rows($sql1);
echo "Table: " . $row[0] . ": " . $jml_record record . "<br>";
$jmltbl++;
$jml_record += $jml_record;
}
echo "--------------------------------<br>$jmltbl Tables, $jml_record > records.";
Based on @Nathan's answer above, but without needing to "remove the final union" and with the option to sort the output, I use the following SQL. It generates another SQL statement which then just run:
select CONCAT( 'select * from (\n', group_concat( single_select SEPARATOR ' UNION\n'), '\n ) Q order by Q.exact_row_count desc') as sql_query
from (
SELECT CONCAT(
'SELECT "',
table_name,
'" AS table_name, COUNT(1) AS exact_row_count
FROM `',
table_schema,
'`.`',
table_name,
'`'
) as single_select
FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = 'YOUR_SCHEMA_NAME'
and table_type = 'BASE TABLE'
) Q
You do need a sufficiently large value of group_concat_max_len server variable but from MariaDb 10.2.4 it should default to 1M.
I don't know why this has to be so hard but that's life. Here's my bash script that performs actual counts. Just save this as (e.g. count_rows.sh ), make it executable (e.g. chmod 755 count_rows.sh ), and run it (e.g. ./count_rows.sh )
#!/bin/bash
readarray -t TABLES < <(mysql --skip-column-names -u myuser -pmypassword mydbname -e "show tables")
# now we have an array like:
# TABLES='([0]="customer" [1]="order" [2]="product")'
# You can print out the array with:
#declare -p TABLES
for i in "${TABLES[@]}"
do
#echo $i
COUNT=$(mysql --skip-column-names -u username -pmypassword mydbname -e "select count(*) from $i")
echo $i : $COUNT
done
Like many others, I have difficulty getting an accurate value on the INFORMATION_SCHEMA tables with InnoDB, and would infinitely benefit from being able to make a query that depends on count(), and, hopefully, do it in one, single query.
First, make sure to enable massive group_concats:
SET SESSION group_concat_max_len = 1000000;
Then run this query to get the resultant query you'll run for your database.
SELECT CONCAT('SELECT ', GROUP_CONCAT(table1.count SEPARATOR ',\n')) FROM (
SELECT concat('(SELECT count(id) AS \'',table_name,' Count\' ','FROM ',table_name,') AS ',table_name,'_Count') AS 'count'
FROM information_schema.tables
WHERE table_schema = '**YOUR_DATABASE_HERE**'
) AS table1
This will generate output such as...
SELECT (SELECT count(id) AS 'table1 Count' FROM table1) AS table1_Count,
(SELECT count(id) AS 'table2 Count' FROM table2) AS table2_Count,
(SELECT count(id) AS 'table3 Count' FROM table3) AS table3_Count;
This in turn gave the following results:
*************************** 1. row ***************************
table1_Count: 1
table2_Count: 1
table3_Count: 0
The code below generation the select query for all tales. Just delete last "UNION ALL" select all result and paste a new query window to run.
SELECT
concat('select ''', table_name ,''' as TableName, COUNT(*) as RowCount from ' , table_name , ' UNION ALL ') as TR FROM
information_schema.tables where
table_schema = 'Database Name'