How do I get the column name of two tables in a single query ?
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
where table_name = 'table_name';
This works for single table. But if I try
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
where table_name = 'table1'
AND
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
where table_name = 'table2';
This throws error.
Error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT column_name FROM INFORMATION_SCHEMA.COLUMNS where table_name = 'table2' ' at line 5
Error Code: ER_PARSE_ERROR
Different queries will be put together using UNION ALL (or UNION only if it's necessary to exclude identic values which appear in both queries):
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'table1'
UNION ALL -- here use "UNION ALL" instead of "AND"
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'table2';
Since you want to get data from the same table, you don't need two queries at all.
Just use an IN clause...
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name IN ('table1','table2');
...or use OR:
SELECT column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_name = 'table1'
OR table_name = 'table2';
if you want to select 2 columns from different tables, you need to add some relation between them.
On the basis of that relationship, you can fetch data from two different tables.
Please check the link: https://www.w3schools.com/mysql/mysql_join.asp
Hope it will solve your problem.
Related
I am wondering if it is possible to integrate, in MYSQL, the functions LEAST / GREATEST together with SELECT column_name FROM information_schema.table name. If possible, it would save me a lot of time.
The code i current have is simplified below:
SELECT
tb.date,
LEAST(tb.test_0, tb.test_1, tb.test_2) AS min_value,
FROM mySchema.myTable AS tb;
This code works. However, I don't want to have to write down all the 'tb.test_', so I am working on a query using LIKE function. The following query produces as output a table with all the column_names of my db.
SELECT COLUMN_NAME FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = 'mySchema'
AND TABLE_NAME = 'myTable'
and COLUMN_NAME LIKE 'test_%';
Therefore, I was expecting to combine both functions and produce something like:
SELECT
tb.date,
LEAST(
SELECT COLUMN_NAME FROM information_schema.COLUMNS
WHERE TABLE_SCHEMA = 'mySchema'
AND TABLE_NAME = 'myTable'
and COLUMN_NAME LIKE 'test_%'
) AS min_value,
FROM mySchema.myTable AS tb;
I would need to find all %phone% instances from all tables in a specific DB.
This is my script i'm trying with yet still getting all the DBs (I need only from DB1):
use DB1;
SELECT *
FROM
information_schema.columns
WHERE
column_name LIKE '%phone%';
I also tried writing like this:
SELECT *
FROM
DB1.information_schema.columns
WHERE
column_name LIKE '%phone%';
but I got a SQL Error [1064] [42000] for that syntax.
What would be the correct way to query this?
There's only one INFORMATION_SCHEMA database for all the databases on the server. The table database is in the table_schema column of the columns table.
SELECT *
FROM information_schema.columns
WHERE table_schema = 'DB1' AND column_name LIKE '%phone%';
I used the following for '%email%'
and it worked.
So i guess it would for for you too:
SELECT
DISTINCT TABLE_NAME
FROM
INFORMATION_SCHEMA.COLUMNS
WHERE
COLUMN_NAME LIKE ('%phone%') AND TABLE_SCHEMA='DB1';
use the parameter TABLE_SCHEMA, to select your scheam/database
SELECT *
FROM
information_schema.columns
WHERE
column_name LIKE '%phone%'
AND TABLe_SCHEMA = 'DB1';
I have a table with 300+ column. Looking for a specific column is like nightmare. Is there any query where If I would like to search for columns stats with 'grand' can be listed...
You can use show columns from table with where. Try the following query,
SHOW COLUMNS FROM tablename WHERE field like 'grand%';
Just put in your tablename after FROM and it would work.
select * from myTable where mycolumn like 'grand%'
Try this.
SELECT
table_name,
column_name,
data_type,
ordinal_position
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_schema = 'DatabaseName' --- the database you want to search
AND table_name = 'yourTableName'
AND column_name LIKE '%Grand' ;
This one worked for me. Its shows all columns and table in entire database
SELECT TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE column_name OR table_name LIKE '%sale%';
Is there any way of listing all tables and columns names using UNION or a JOIN?
If you want all tables and columns in a schema, no need to use UNION and BIND, just joining the data in
information_schema.columns
information_schema.tables
will do the trick. See details on both at:
http://dev.mysql.com/doc/refman/5.0/en/information-schema.html
An example query that would achieve the minimum of what appears to be your goal would be:
SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
But again, joining the two based on table name might be needed -- depends on your precise goal.
If you just want the tables with UNION/BIND in the names and the columns with UNION/BIND in the names, two simple queries to do that would be:
SELECT TABLE_NAME from INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '%UNION%' or TABLE_NAME LIKE '%BIND%'
and
SELECT TABLE_NAME, COLUMN_NAME from INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE '%UNION%' or TABLE_NAME LIKE '%BIND%'
You can use INFORMATION_SCHEMA. The query below would be useful:
SELECT 'COLUMN' as Match_Type,
column_name as MATCH_NAME,
table_name,
table_schema
FROM INFORMATION_sCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE '%UNION%'
OR COLUMN_NAME LIKE '%BIND%'
UNION ALL
SELECT 'TABLE' as Match_Type,
table_name as MATCH_NAME,
table_name,
table_schema
FROM INFORMATION_sCHEMA.TABLES
WHERE TABLE_NAME LIKE '%UNION%'
OR TABLE_NAME LIKE '%BIND%'
I have 2-3 different column names that I want to look up in the entire database and list out all tables which have those columns. Is there any easy script?
To get all tables with columns columnA or ColumnB in the database YourDatabase:
SELECT DISTINCT TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME IN ('columnA','ColumnB')
AND TABLE_SCHEMA='YourDatabase';
SELECT TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE '%wild%';
More simply done in one line of SQL:
SELECT * FROM information_schema.columns WHERE column_name = 'column_name';
SELECT DISTINCT TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE column_name LIKE 'employee%'
AND TABLE_SCHEMA='YourDatabase'
In older MySQL versions or some MySQL NDB Cluster versions that do not have information_schema, you can dump the table structure and search the column manually.
mysqldump -h$host -u$user -p$pass --compact --no-data --all-databases > some_file.sql
Now search the column name in some_file.sql using your preferred text editor, or use some nifty AWK scripts.
And a simple sed script to find the column. Just replace COLUMN_NAME with yours:
sed -n '/^USE/{h};/^CREATE/{H;x;s/\nCREATE.*\n/\n/;x};/COLUMN_NAME/{x;p};' <some_file.sql
USE `DATABASE_NAME`;
CREATE TABLE `TABLE_NAME` (
`COLUMN_NAME` varchar(10) NOT NULL,
You can pipe the dump directly in sed, but that's trivial.
For those searching for the inverse of this, i.e. looking for tables that do not contain a certain column name, here is the query...
SELECT DISTINCT TABLE_NAME FROM information_schema.columns WHERE
TABLE_SCHEMA = 'your_db_name' AND TABLE_NAME NOT IN (SELECT DISTINCT
TABLE_NAME FROM information_schema.columns WHERE column_name =
'column_name' AND TABLE_SCHEMA = 'your_db_name');
This came in really handy when we began to slowly implement use of InnoDB's special ai_col column and needed to figure out which of our 200 tables had yet to be upgraded.
Use this one line query. Replace desired_column_name by your column name.
SELECT TABLE_NAME FROM information_schema.columns WHERE column_name = 'desired_column_name';
If you want to "get all tables only", then use this query:
SELECT TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME like '%'
and TABLE_SCHEMA = 'tresbu_lk'
If you want "to get all tables with columns", then use this query:
SELECT DISTINCT TABLE_NAME, COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE column_name LIKE '%'
AND TABLE_SCHEMA='tresbu_lk'
select distinct table_name
from information_schema.columns
where column_name in ('ColumnA')
and table_schema='YourDatabase';
and table_name in
(
select distinct table_name
from information_schema.columns
where column_name in ('ColumnB')
and table_schema='YourDatabase';
);
That ^^ will get the tables with ColumnA and ColumnB instead of ColumnA or ColumnB like the accepted answer
SELECT DISTINCT TABLE_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE COLUMN_NAME LIKE '%city_id%' AND TABLE_SCHEMA='database'
The problem with information_schema is that it can be terribly slow. It is faster to use the SHOW commands.
After you select the database you first send the query SHOW TABLES. And then you do SHOW COLUMNS for each of the tables.
In PHP that would look something like
$res = mysqli_query("SHOW TABLES");
while($row = mysqli_fetch_array($res))
{ $rs2 = mysqli_query("SHOW COLUMNS FROM ".$row[0]);
while($rw2 = mysqli_fetch_array($rs2))
{ if($rw2[0] == $target)
....
}
}