SQLite equivalent to ISNULL NVL IFNULL or COALESCE

Question

I d like to avoid having many checks like the following in my code   myObj someStringField   rdr IsDBNull someOrdinal                                 string Empty                                rdr GetString someOrdinal     I figured I could just have my query take care of the nulls by doing something like this   SELECT myField1   isnull  myField1       FROM myTable1 WHERE myField1   someCondition   I m using SQLite though and it doesn t seem to recognize the isnull function  I ve also tried some equivalent ones recognized in other databases  NVL    IFNULL   and COALESCE     but SQLite doesn t seem to recognize any of them   Does anyone have any suggestions or know of a better way to do this  Unfortunately the database doesn t have default values for all fields  Plus  I need to use some LEFT JOIN clauses in some cases  where some of the fields returned will be null because the matching record in the LEFT JOIN table will not exist

User · Answer

If there is not ISNULL   method  you can use this expression instead   CASE WHEN fieldname IS NULL THEN 0 ELSE fieldname END   This works the same as ISNULL fieldname  0

User · Answer

Try this  ifnull X Y      e g   select ifnull InfoDetail     InfoDetail  -- this will replace null with    select ifnull NULL  THIS IS NULL   -- More clearly       The ifnull   function returns a copy of its first non-NULL argument  or NULL if both arguments are NULL  Ifnull   must have exactly 2 arguments  The ifnull   function is equivalent to coalesce   with two arguments

User · Answer

Use IS NULL or IS NOT NULL in WHERE-clause instead of ISNULL   method   SELECT myField1 FROM myTable1 WHERE myField1 IS NOT NULL

User · Answer

IFNULL  see here  http   www sqlite org lang corefunc html ifnull  no brackets around the function

User · Answer

For the equivalent of NVL   and ISNULL   use   IFNULL column  altValue   column   The column you are evaluating   altValue   The value you want to return if  column  is null   Example   SELECT IFNULL middle name   N A   FROM person    Note  The COALESCE   function works the same as it does for other databases    Sources    COALESCE   Function  w3schools  SQL As Understood By SQLite  SQLite website

User · Answer

You can easily define such function and use it then   ifnull  lt - function x y      if is na x   TRUE       return  y    else      return  x       or same minified version   ifnull  lt - function x y   if is na x   TRUE  return  y  else return  x

[.net] SQLite equivalent to ISNULL(), NVL(), IFNULL() or COALESCE()

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