How do I count columns of a table
SELECT count(*)
FROM information_schema.columns
WHERE table_name = 'tbl_ifo'
I think you need also to specify the name of the database:
SELECT COUNT(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_schema = 'SchemaNameHere'
AND table_name = 'TableNameHere'
if you don't specify the name of your database, chances are it will count all columns as long as it matches the name of your table. For example, you have two database: DBaseA and DbaseB
, In DBaseA
, it has two tables: TabA(3 fields), TabB(4 fields). And in DBaseB
, it has again two tables: TabA(4 fields), TabC(4 fields).
if you run this query:
SELECT count(*)
FROM information_schema.columns
WHERE table_name = 'TabA'
it will return 7 because there are two tables named TabA
. But by adding another condition table_schema = 'SchemaNameHere'
:
SELECT COUNT(*)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_schema = 'DBaseA'
AND table_name = 'TabA'
then it will only return 3.
$cs = mysql_query("describe tbl_info");
$column_count = mysql_num_rows($cs);
Or just:
$column_count = mysql_num_rows(mysql_query("describe tbl_info"));
To count the columns of your table precisely, you can get form information_schema.columns
with passing your desired Database(Schema) Name and Table Name.
Reference the following Code:
SELECT count(*)
FROM information_schema.columns
WHERE table_schema = 'myDB'
AND table_name = 'table1';
I have a more general answer; but I believe it is useful for counting the columns for all tables in a DB:
SELECT table_name, count(*)
FROM information_schema.columns
GROUP BY table_name;