I want to replace two things in one select statement. Now I can replace one character at a time. But as per my requirment, I need to replace two things in one statement.I want to replace one special character by Zero and another is this data is stored in multiple lines. I want to fetch this data in one line.
select replace(message,chr(ACII_Value),0)
from my_table -- I can replace special character by zero using this.
select (message,chr(10),' ')
from my_table -- I can put all data in single line using this.
Now I want to do this in one select statement.
select replace( replace( message, chr(ACII_Value), 0), chr(10), ' ')
from my_table;
An alternative is the TRANSLATE function:
select translate(message, chr(ASCII_Value)||chr(10), '0 ') from my_table;
Although if you're only replacing two characters, I'd go with #schurik's answer since it uses a simpler, more common function.
Related
I have a large list of SQL commands such as
SELECT * FROM TEST_TABLE
INSERT .....
UPDATE .....
SELECT * FROM ....
etc. My goal is to parse this list into a set of results so that I can easily determine a good count of how many of these statements are SELECT statements, how many are UPDATES, etc.
so I would be looking at a result set such as
SELECT 2
INSERT 1
UPDATE 1
...
I figured I could do this with Regex, but I'm a bit lost other than simply looking at everything string and comparing against 'SELECT' as a prefix, but this can run into multiple issues. Is there any other way to format this using REGEX?
You can add the SQL statements to a table and run them through a SQL query. If the SQL text is in a column called SQL_TEXT, you can get the SQL command type using this:
upper(regexp_substr(trim(regexp_replace(SQL_TEXT, '\\s', ' ')),
'^([\\w\\-]+)')) as COMMAND_TYPE
You'll need to do some clean up to create a column that indicates the type of statement you have. The rest is just basic aggregation
with cte as
(select *, trim(lower(split_part(regexp_replace(col, '\\s', ' '),' ',1))) as statement
from t)
select statement, count(*) as freq
from cte
group by statement;
SQL is a language and needs a parser to turn it from text into a structure. Regular expressions can only do part of the work (such as lexing).
Regular Expression Vs. String Parsing
You will have to limit your ambition if you want to restrict yourself to using regular expressions.
Still you can get some distance if you so want. A quick search found this random example of tokenizing MySQL SQL statements using regex https://swanhart.livejournal.com/130191.html
Is it possible to check if a row contains a string without conisdering spaces?
Suppose I have a table like the one above. I want to know if the query column contains a string that may have different consecutive number of space than the one stored or vice versa?
For example: the first row's query is select id, username from postgresql, and the one I want to know if stored in the table is:
select id, username
from postgresql
That is to say the one that I want to know if exists in the table is indented differently and hence has different number of space.
You can use REGEXP_REPLACE; this will likely be very slow on large data set.
SELECT * from table
where REGEXP_REPLACE('select id, username from postgresql ', '\s+$', '') = REGEXP_REPLACE(query, '\s+$', '')
I think you would phrase this as:
where $str ~ replace('select id, username from postgresql', ' ', '[\s]+')
Note: This assumes that your string does not have other regular expression special characters.
I feel like this should be simple enough to do, but have not found any solutions that didn't use replace so far. I have the following select statement I am running, and for some of the columns there are commas separating the values. I would like to replace these commas with semicolons, however I only want to do it in the select statement. I don't want it to alter the values in the tables at all. This is not a one off statement either, or I'd just replace all the commas with semicolons and then revert back.
SELECT a.Category_Id, a.Category_Name, ISNULL(b.Category_Alias, '') as Category_Alias,
ISNULL(b.SUPPORT_NAMES, '') as SUPPORT_NAMES
FROM Categories a
INNER JOIN CategoryInfo b on b.Category_Id=a.Category_Id
For the Category_Alias column, the records are actually stored like CS, Customer Support and I want that to show up as CS; Customer Support just for the select statement.
I believe you may be confused as to what the REPLACE function is doing. You can use REPLACE within your SELECT statement without altering the data in the database:
SELECT REPLACE(MyField, ',', ';') AS NewFieldName
FROM MyTable
I believe you don't want to replace the value physically in the table, but ok to replace on select
So you can
Select REPLACE(ColumnName,',',';')
From TableName
Most SQL servers implement an inline replace function. Most of them are named replace(), and can also be used in a select statement.
Example from MySQL:
SELECT field, REPLACE(field,',',';') FROM my_table;
I am using Postgresql and I need to run a query where I do a SELECT DISTINCT on a single string column. However I don't want to select the column as is, I need to substring it on the first occurrence of this string ' ('.
I do not know how to do this substring part..
Here is an example of the query without the substring part:
SELECT DISTINCT ON (Table.Column1) Table.Column2
FROM Table
ORDER BY Table.Column1
I am not sure what functions to use in postgres or possibly I need to use plpgsql to do this?
I managed to work this out. The function to be used is SPLIT_PART. Which takes three parameters ColumnName, Characters, And the substring occurance.
Here is an example of how I have used it.
SELECT DISTINCT ON (SPLIT_PART(Table.Column1, ' )', 1)) Table.Column2
FROM Table
ORDER BY SPLIT_PART(Table.Column1, ' )', 1)
I am trying to find if a certain column requires TRIM function on it.
How can I find out if this column in a table has records that have white space either before or after the actual data.
You can check it using the TRIM function itself, not the most efficient but accurate:
Select *
From TableA
Where MyColumn <> TRIM(MyColumn)
Though if you're checking then turning around to trim anyway, you probably want to just do it in the first place, like this:
Select TRIM(MyColumn) as TrimmedMyColumn
From TableA
A quick and dirty way
WHERE LENGTH(TRIM(COL1)) <> LENGTH(COL1)
So why can't you use the following to find the leading spaces? I've been able to identify the records with leading spaces this way and using '% ' to find the trailing spaces.
SELECT mycolumn
FROM my_table
WHERE mycolumn LIKE ' %'
I've also used the following to remove both the leading and trailing spaces
Update My_table set Mycolumn = TRIM(Mycolumn)
which seems to work just fine.
You could use regular expressions in Oracle.
Example:
select * from your_table
where regexp_like(your_column, '^[ ]+.*')
or regexp_like(your_column, '.*[ ]+$')
select data1, length(data1)-length(replace(data1,' ','')) from t;
Following query will retrieve rows when one of Table fields T$DSCA has trailing spaces at the end:
SELECT * from TABLE_NAME A WHERE RAWTOHEX(SUBSTR(A.T$DSCA, LENGTH(T$DSCA),1)) ='A0' AND TRIM(T$DSCA) is not null;