Replacing the missing values of while comparing 2 tables
0
I have 2 tables on my database and would like to compare both the tables and replace the missing values from one table to another. For example.
TABLE 1
column 1 column 2
ab 3
ab -
a 1
a -
b -
b 2
ab 3
ab -
a 1
a -
b 2
TABLE 2
column 1 column 2
ab 3
a 1
b 2
I want to compare both the tables on column 1 and replace only the missing values on column 2 and not touch the values that are already there.
Is this possible on SQL or using pandas on python? Any solution would be helpful.
python sql pandas python-2.7 sqlite
asked Nov 22 '18 at 5:34
MattMatt
546
add a comment |
0
I have 2 tables on my database and would like to compare both the tables and replace the missing values from one table to another. For example.
TABLE 1
column 1 column 2
ab 3
ab -
a 1
a -
b -
b 2
ab 3
ab -
a 1
a -
b 2
TABLE 2
column 1 column 2
ab 3
a 1
b 2
I want to compare both the tables on column 1 and replace only the missing values on column 2 and not touch the values that are already there.
Is this possible on SQL or using pandas on python? Any solution would be helpful.
python sql pandas python-2.7 sqlite
asked Nov 22 '18 at 5:34
MattMatt
546
1
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27
add a comment |
0
0
0
I have 2 tables on my database and would like to compare both the tables and replace the missing values from one table to another. For example.
TABLE 1
column 1 column 2
ab 3
ab -
a 1
a -
b -
b 2
ab 3
ab -
a 1
a -
b 2
TABLE 2
column 1 column 2
ab 3
a 1
b 2
I want to compare both the tables on column 1 and replace only the missing values on column 2 and not touch the values that are already there.
Is this possible on SQL or using pandas on python? Any solution would be helpful.
python sql pandas python-2.7 sqlite
asked Nov 22 '18 at 5:34
MattMatt
546
I have 2 tables on my database and would like to compare both the tables and replace the missing values from one table to another. For example.
TABLE 1
column 1 column 2
ab 3
ab -
a 1
a -
b -
b 2
ab 3
ab -
a 1
a -
b 2
TABLE 2
column 1 column 2
ab 3
a 1
b 2
I want to compare both the tables on column 1 and replace only the missing values on column 2 and not touch the values that are already there.
Is this possible on SQL or using pandas on python? Any solution would be helpful.
python sql pandas python-2.7 sqlite
python sql pandas python-2.7 sqlite
asked Nov 22 '18 at 5:34
MattMatt
546
asked Nov 22 '18 at 5:34
MattMatt
546
edited Nov 22 '18 at 11:14
Matt
asked Nov 22 '18 at 5:34
MattMatt
546
asked Nov 22 '18 at 5:34
MattMatt
546
asked Nov 22 '18 at 5:34
MattMatt
546
546
1
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27
add a comment |
1
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27
1
1
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27
add a comment |
1 Answer
1
active
oldest
votes
-2
## SQL Query be like ##
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL.
UPDATE table1
SET table1.Col2=table2.Col2
FROM table1
JOIN table2
ON table1.col1=table2.col1
where table1.col2 IS NULL
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
-2
## SQL Query be like ##
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL.
UPDATE table1
SET table1.Col2=table2.Col2
FROM table1
JOIN table2
ON table1.col1=table2.col1
where table1.col2 IS NULL
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
add a comment |
-2
## SQL Query be like ##
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL.
UPDATE table1
SET table1.Col2=table2.Col2
FROM table1
JOIN table2
ON table1.col1=table2.col1
where table1.col2 IS NULL
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
add a comment |
-2
-2
-2
## SQL Query be like ##
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL.
UPDATE table1
SET table1.Col2=table2.Col2
FROM table1
JOIN table2
ON table1.col1=table2.col1
where table1.col2 IS NULL
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
## SQL Query be like ##
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL.
UPDATE table1
SET table1.Col2=table2.Col2
FROM table1
JOIN table2
ON table1.col1=table2.col1
where table1.col2 IS NULL
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
edited Nov 25 '18 at 4:00
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
answered Nov 22 '18 at 9:00
Md. Mehedi HassanMd. Mehedi Hassan
176
176
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
add a comment |
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
Please add some context.
– Matthieu Brucher
Nov 22 '18 at 10:18
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
This query replaces the column2 value of Table2 to the column2 of Table1 which are NULL. @MatthieuBrucher
– Md. Mehedi Hassan
Nov 22 '18 at 11:28
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Please put this in your answer. It should be self-consistent.
– Matthieu Brucher
Nov 22 '18 at 11:51
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Would you know how you would write it in sqlite? @Md.MehediHassan
– Matt
Nov 22 '18 at 13:19
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
Sorry buddy, I'm not working in sqlite yet @MatthieuBrucher
– Md. Mehedi Hassan
Nov 25 '18 at 4:01
add a comment |
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1
Consider table 1 as the master and table 2 as the loop up table. All I wanted to do was to look up table 1 and replace the significant values on table 1. There are not always 2 rows of every thing. I have edited that bit. To give you more context table 1 has a few million rows and table 2 has the look ups for them. Please do let me know if this answers your questions.
– Matt
Nov 22 '18 at 11:20
Makes sense - I think the two answers below will achieve that.
– DaveyDaveDave
Nov 22 '18 at 11:27