[mysql] Detect if value is number in MySQL

Is there a way to detect if a value is a number in a MySQL query? Such as

FROM myTable 
WHERE isANumber(col1) = true

This question is related to mysql sql where-clause

The answer is

This should work in most cases.

SELECT * FROM myTable WHERE concat('',col1 * 1) = col1

It doesn't work for non-standard numbers like

  • 1e4
  • 1.2e5
  • 123. (trailing decimal)

I recommend: if your search is simple , you can use `

column*1 = column

` operator interesting :) is work and faster than on fields varchar/char

SELECT * FROM myTable WHERE column*1 = column;

ABC*1 => 0 (NOT EQU **ABC**)
AB15*A => 15 (NOT EQU **AB15**)
15AB => 15 (NOT EQU **15AB**)
15 => 15 (EQUALS TRUE **15**)

Still missing this simple version:

SELECT * FROM myTable WHERE `col1` + 0 = `col1`

(addition should be faster as multiplication)

Or slowest version for further playing:

CASE WHEN `col1` + 0 = `col1` THEN 1 ELSE 0 END AS `IS_NUMERIC` 
FROM `myTable`

WHERE col1 REGEXP '^[+-]?[0-9]*([0-9]\\.|[0-9]|\\.[0-9])[0-9]*(e[+-]?[0-9]+)?$'

Will also match signed decimals (like -1.2, +0.2, 6., 2e9, 1.2e-10).


drop table if exists myTable;
create table myTable (col1 varchar(50));
insert into myTable (col1) 
  values ('00.00'),('+1'),('.123'),('-.23e4'),('12.e-5'),('3.5e+6'),('a'),('e6'),('+e0');

  col1 + 0 as casted,
  col1 REGEXP '^[+-]?[0-9]*([0-9]\\.|[0-9]|\\.[0-9])[0-9]*(e[+-]?[0-9]+)?$' as isNumeric
from myTable;


col1   |  casted | isNumeric
00.00  |       0 |         1
+1     |       1 |         1
.123   |   0.123 |         1
-.23e4 |   -2300 |         1
12.e-5 | 0.00012 |         1
3.5e+6 | 3500000 |         1
a      |       0 |         0
e6     |       0 |         0
+e0    |       0 |         0


If your data is 'test', 'test0', 'test1111', '111test', '111'

To select all records where the data is a simple int:

FROM myTable 
WHERE col1 REGEXP '^[0-9]+$';

Result: '111'

(In regex, ^ means begin, and $ means end)

To select all records where an integer or decimal number exists:

FROM myTable 
WHERE col1 REGEXP '^[0-9]+\\.?[0-9]*$'; - for 123.12

Result: '111' (same as last example)

Finally, to select all records where number exists, use this:

FROM myTable 
WHERE col1 REGEXP '[0-9]+';

Result: 'test0' and 'test1111' and '111test' and '111'

This answer is similar to Dmitry, but it will allow for decimals as well as positive and negative numbers.

select * from table where col1 REGEXP '^[[:digit:]]+$'

You can use regular expression for the mor detail https://dev.mysql.com/doc/refman/8.0/en/regexp.html

I used this ^([,|.]?[0-9])+$. This is allows handle to the decimal and float number

    myTextField REGEXP "^([,|.]?[0-9])+$"

Another alternative that seems faster than REGEXP on my computer is

SELECT * FROM myTable WHERE col1*0 != col1;

This will select all rows where col1 starts with a numeric value.

SELECT * FROM myTable WHERE sign (col1)!=0

ofcourse sign(0) is zero, but then you could restrict you query to...

SELECT * FROM myTable WHERE sign (col1)!=0 or col1=0

UPDATE: This is not 100% reliable, because "1abc" would return sign of 1, but "ab1c" would return zero... so this could only work for text that does not begins with numbers.

I have found that this works quite well

if(col1/col1= 1,'number',col1) AS myInfo

Returns numeric rows

I found the solution with following query and works for me:

SELECT * FROM myTable WHERE col1 > 0;

This query return rows having only greater than zero number column that col1

Returns non numeric rows

if you want to check column not numeric try this one with the trick (!col1 > 0):

SELECT * FROM myTable WHERE !col1 > 0;

You can use Regular Expression too... it would be like:

SELECT * FROM myTable WHERE col1 REGEXP '^[0-9]+$';

Reference: http://dev.mysql.com/doc/refman/5.1/en/regexp.html

use a UDF (user defined function).

CREATE FUNCTION isnumber(inputValue VARCHAR(50))
    IF (inputValue REGEXP ('^[0-9]+$'))
      RETURN 1;
      RETURN 0;
    END IF;

Then when you query

select isnumber('383XXXX') 

--returns 0

select isnumber('38333434') 

--returns 1

select isnumber(mycol) mycol1, col2, colx from tablex; -- will return 1s and 0s for column mycol1

--you can enhance the function to take decimals, scientific notation , etc...

The advantage of using a UDF is that you can use it on the left or right side of your "where clause" comparison. this greatly simplifies your SQL before being sent to the database:

 SELECT * from tablex where isnumber(columnX) = isnumber('UnkownUserInput');

hope this helps.

you can do using CAST

  SELECT * from tbl where col1 = concat(cast(col1 as decimal), "")

Try Dividing /1

select if(value/1>0 or value=0,'its a number', 'its not a number') from table

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