How to check the string length using grep? - bash

Question

I have a lot of Teradata SQL files. The example file look like below:
create multiset volatile table abcde_fghijk_lmnop as(
select
a.oppnl3_budssstr as nip,
from T45_BACKJJU_33KUT.BRANDFO9 a
) with data on commit preserve rows;
create multiset volatile table mari_lee as(
select
b.getter3,
from maleno_fugi75_pratq b
) with data on commit preserve rows;
create multiset table blabla1 as (
select
a.atomic94,
from b4ty7_manto.pretyu59_bxcx a
) with data on commit preserve rows;
CREATE multiset table blablabla2 AS (
SELECT
a.prompter_to12
FROM tresh_old44 a
) WITH data on commit preserve rows;
CREATE multiset table blablablabla3 AS (
SELECT
c.future_opt86
FROM GFTY_133URO c
) WITH data on commit preserve rows;
I want to create a grep method which can count the length of the table name, which can't exceed 10 signs.
I have created a few greps, but none of them work, and I don't know why. What I have done wrong?
for f in /path/to/sql/files/*.sql; do
if grep -q ' table \{1,10\}' "$f"; then
echo "correct length of table name $f"
fi
done
other greps which I used:
if grep -q ' table \{1,10\} as ' "$f"; then
if grep -q ' table \[[:alnum:]]\{1,10\} ' "$f"; then
if grep -q ' table\[[:space:]][[:alnum:]]\{1,10\} ' $f; then

Answer 1

There are a couple of problems with your attempts. Firstly, it looks like you're escaping the [ in some of your bracket expressions, which means that the [ will be interpreted as a literal character instead. Secondly, you need to take care to match 1 to 10 legal characters, followed by a different character.
This pattern does what you want (I removed the -q so that you can see which table definitions match):
$ grep ' table [[:alnum:]_]\{1,10\}[^[:alnum:]_]' file
create multiset volatile table mari_lee as(
create multiset table blabla1 as (
CREATE multiset table blablabla2 AS (
This pattern matches 1 to 10 alphanumeric characters or underscores, followed by a different character, meaning that the longer table names no longer match.
As it appears that the casing is inconsistent, you should probably also use the -i switch to grep, to enable case-insensitive matching. Otherwise, any definitions that use "TABLE" would not match.

Answer 2

Use grep with word boundary to list only valid table names:
grep -E 'table +.{1,10}\b' "$f"
create multiset volatile table mari_lee as(
create multiset table blabla1 as (
CREATE multiset table blablabla2 AS (
To suppress output use -q and check return status:
grep -qE 'table +.{1,10}\b' "$f"