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[rdb@mdb tmp] $echo TOM | awk'{print "select * from A where name='\''" $1 "\'"}''

Select * from A where name='TOM'

[rdb@mdb tmp] $echo TOM | awk'{print "select * from A where name='\'" $1 "\'"}''

Select * from A where name='TOM'

[rdb@mdb tmp] $

The name part of both is enlarged as follows:

Name='\ "$1"\'"

Name='\ "$1"\'"

The former has two more single quotes before the $1 double quotation marks than the latter, but why do the two have the same effect? my understanding is that the two extra single quotes have no internal value and are empty, so the effect is the same. if you add a few more single quotes, for example:

Echo TOM | awk'{print "select * from A where name='\'" $1 "\'"}''

When referencing a concatenated field variable in awk's print, the variable should be enclosed in double quotation marks:

"$1"

Then add single quotation marks to the value, and each single quote needs to be escaped. The escape rule is: two single quotation marks, and then add\ 'inside it. After completion, it is:'\', and when enlarged is:'\'.

It's connected to:'$1'.

This is the second name='\'$1'\'

On the question of referencing shell variables:

To use the shell variable in awk, you need to use "'$a'" with double quotation marks and single quotation marks.

For example:

[rdb@mdb tmp] $axi10

[rdb@mdb tmp] $echo 90 | awk'{print "" $1 "/"'$a' "=" $1 / "" $a' "}'

90, 10, 10, 9.

[rdb@mdb tmp] $

Enlarged to: echo 90 | awk'{print "" $1 "/"'$a'"=" $1 / "" $a'"}'

Function getcmdstat_sql ()

{

Grep cmdstat_ 13_20170519102523.info_all | awk-F "[: =,] +" {print "insert into tbl_rdb_cmdstats (dc_area,node_name,node_ip,chk_time,statname,total_calls,total_timing) values ('\'${dc_area}'\', ${1}'\','\'${2}'\', to_date ('\'${fn_date}'\') '\' yyyy-mm-dd hh34:mi:ss'\'),'\'"$1"'\','\'"$3"'\', trunc ('"$5"'\'/ 1000amp 1000) "}'> > / tmp/c.sql

}

Getcmdstat_sql "$node_name"$node_ip"

-F "[: =,] +" represents:, =, "colon, equal sign, comma are all delimiters.

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