Why the value of the id=3 is empty?-CodePudding

Update a set name=name + (select b.n ame from b where b.i d=Anderson d)

The value of the modified after the completion of a table id=3 why is empty

CodePudding user response:

String cannot directly use + addition, this statement will be an error

CodePudding user response:

reference 1st floor nayi_224 response:

string cannot directly use + addition, this statement complains

His library, this should not be oracle

CodePudding user response:

refer to the second floor selling fruit net reply:

Quote: refer to 1st floor nayi_224 response:

String can't directly use + addition, this statement complains

His library, this should not be oracle

Basically have combined with a null result is empty this feature

CodePudding user response:

If is the ORACLE database, you can try this,
Update a set name=(select NVL (a.n ame, ' ') | | NVL (b.n ame, ' ') from b where b.i d=Anderson, d)

CodePudding user response:

Can not oracle database, if used with isnull or add a condition exists, only updated in table b in a line to find the corresponding id

CodePudding user response:

A is equal to 3 to value is null, but according to the understanding should be a=3 values

CodePudding user response:

Update the set b b.t name=b.t name | | (select a.t name from a where Anderson, d=b.i d);
Oracle should be so, name=directly, it id=3 or is empty

CodePudding user response:

Null all +=null

CodePudding user response:

Yes, this is the character + what meaning do you use? Didn't understand the wrong you need to change + to | |

CodePudding user response:

Update a set name=name | | (select b.n ame from b where b.i d=Anderson, d)

CodePudding user response:

Should be null

CodePudding user response:

Null value computation