Question

I am executing a Command

mysql -uroot -proot -Bse "select Concat('SHOW CREATE TABLE ',TABLE_SCHEMA ,'.',TABLE_NAME,'\\G') from information_schema.tables where TABLE_SCHEMA Not IN('mysql','information_schema','performance_schema');"

I want output as

SHOW CREATE TABLE sakila.category\G
SHOW CREATE TABLE sakila.city\G
SHOW CREATE TABLE sakila.country\G
SHOW CREATE TABLE sakila.customer\G

But I am getting

SHOW CREATE TABLE sakila.categoryG
SHOW CREATE TABLE sakila.cityG
SHOW CREATE TABLE sakila.countryG
SHOW CREATE TABLE sakila.customerG

Why is this so? Where am I wrong?

UPDATE

If I write

mysql -uroot -proot -Bse "select Concat('SHOW CREATE TABLE ',TABLE_SCHEMA ,'.',TABLE_NAME,'\\\\G') from information_schema.tables where TABLE_SCHEMA Not IN('mysql','information_schema','performance_schema');"

I get output as

SHOW CREATE TABLE sakila.category\\G
SHOW CREATE TABLE sakila.city\\G
SHOW CREATE TABLE sakila.country\\G
SHOW CREATE TABLE sakila.customer\\G

But I only want \G, not \\G.

Answer 1

You need an additional level of escaping: \\\\

You give the query string th MySQL via a shell command line. The shell turns the \\\\ (\\ twice) into two \, i. e. \\. That is because it is enclosed in "s.

MySQL sees the \\\\ as \\ and, as it has its own escaping, uses it as \.

---

EDIT: I don’t understand why, but this doesn’t work with your query.

But by fiddling around with it, one wasily finds out that both \\\\G and \\\G would be the way to go.

Alas, the data is modified on output in the MySQL CLI client. As its output is escaped to allow for \0. \t etc. to be output, it as well has to escape the \ on output.

With the CLI parameter -r or --raw, you can disable that behaviour. (Your s option, however, should be redundant, as it is included in B.) And maybe N wouldbe useful, disabling the headers.

So use -Bre or -NBre instead of -Bse and you are perfectly fine with \\\\G.