Mysql count rows in all tables8/21/2023 ![]() $sql = "SELECT COUNT(p. $districtTot = str_pad ( $districtTot, 3, 0, STR_PAD_LEFT ) ![]() JOIN district d ON d.district_id = z.district_id This function returns 0 if it does not find any matching rows. It is a type of aggregate function whose return type is BIGINT. You need to query only one database called informationschema, which contains all metadata about your databases (table structures, etc). It allows us to count all rows or only some rows of the table that matches a specified condition. For example, you might want to know how many pets you have, or how many pets each owner has, or you might want to perform various kinds of census operations on your animals. Databases keep row counts in their stats tables for planning query execution, but the results are only approximate and can be badly out of date. Solution 1: Dynamically modify the UNION statement based on whether the table exists. Databases are often used to answer the question, How often does a certain type of data occur in a table. The syntax is as follows select count () as anyAliasName from yourTableName To understand the above syntax, let us create a table. $sql = "SELECT COUNT(d.district_id) as districtTot 1 Answer Sorted by: 1 You don't need to query all databases, and anyway you can't. Exact Row Counts for All Tables in MySQL and Postgres Keeping track of your row counts can be helpful for budgeting and capacity planning, yet accurate counts are surprisingly hard to get. To exactly count all rows, you need to use the aggregate function COUNT (). $zonetot = str_pad ( $zonetot, 3, 0, STR_PAD_LEFT ) The HAVING clause gets only groups that have more than 20 orders. ![]() $sql = "SELECT count(zone_id) as zonetot FROM sn_school GROUP BY zone_id" The COUNT() function returns the number of orders for each customerid. $schtot = str_pad ( $schtot, 3, 0, STR_PAD_LEFT ) $sql = "SELECT count(school_id) as schtot FROM sn_school" My question is how many schools are there according to the data in the school table and how many of those schools belong to provinces, districts and zones, is it possible in one mysql query?Ĭurrently I am using 4 separate queries for this and the relevant code is as follows. In my DB schema, there are 4 tables and its relationship as shown in the below attached image. UPDATE 12:03 EDTįor those running 5.7/8.0, you can disable sql_mode in the session, run the query and reset it back. It complains of an invalidate GROUP BY otherwise. SELECT tablerows 'Rows Count' FROM informationschema. I had to set the session's sql_mode to blank because MySQL does not like doing aggregate queries of this nature. You can count all rows per table with the help of aggregate function count (TABLEROWS) from informatioschema.tables. > ,COUNT(val1)+COUNT(val2)+COUNT(val3) count_non_null_vals Query OK, 0 rows affected, 1 warning (0.00 sec) MY PROPOSED QUERY EXECUTED mysql> SET session sql_mode = '' | 3 | bobby | tables | NULL | NULL | NULL | | id | firstname | surname | val1 | val2 | val3 | SELECT SUM(TABLEROWS) FROM INFORMATIONSCHEMA.TABLES WHERE TABLESCHEMA 'yourDatabaseName' Apply the above syntax in order to get the count of records for all tables. Mysql> INSERT INTO mytable (firstname,surname,val1,val2,val3) VALUES To get the count of all the records in MySQL tables, we can use TABLEROWS with aggregate function SUM. YOUR SAMPLE DATA LOADED mysql> DROP DATABASE IF EXISTS codemonkey ![]() INSERT INTO mytable (firstname,surname,val1,val2,val3) VALUES YOUR SAMPLE DATA DROP DATABASE IF EXISTS codemonkey ,COUNT(val1)+COUNT(val2)+COUNT(val3) count_non_null_vals Here is what I did: MY PROPOSED QUERY SET session sql_mode = '' select - Sort the tables by count concat( select from (, - Aggregate rows into a single string connected by unions groupconcat( - Build a select count(. I decided to actually write this out for real. You can use your PHP / Python / Java to craft the SQL since you have 30 columns. Id,COUNT(val1)+COUNT(val2)+COUNT(val3) count_non_null_vals Just use COUNT() function on each column and add them up last SELECT If there are no matching rows, COUNT() returns 0. Returns a count of the number of non-NULL values of expr in the rows retrieved by a SELECT statement. The MySQL TABLES table in the informationschema database provides a tablerows field: SELECT tablename, tablerows FROM INFORMATIONSCHEMA.TABLES WHERE TABLESCHEMA '' But tablerows is only valid for some database engines, whereas for INNODB it is either NULL or not accurate.
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