Problems when making an SQL query with the use of UNION

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Problems when making an SQL query with the use of UNION

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#1 by (0 votes)
#2 by (-1 votes)

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I have the following problem when trying to make this query SQL in MySQL

SELECT *  
 FROM Like__post 
 WHERE id__post_ = 2 
UNION 
SELECT * 
 FROM Post 
 WHERE id__post = 2' me genera el siguiente error '
SELECT * 
 FROM Like__post 
 WHERE id__post_ = 2 
UNION 
SELECT *  
 FROM Post 
 WHERE id__post = 2 LIMIT 0, 25

MySQL said: Documentation # 1222 - The used SELECT statements have a different number of columns'

I really do not know why this error is caused

mysql phpmyadmin

asked by Code tutoriales 14.12.2017 в 15:23

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2 answers

How would you look for a log of a sql database from java Pass data between two fragments [duplicate]

score 0 · Answer 1

The UNION operator is used to combine the result set of two or more SELECT instructions.

And to be able to use it, these three rules must be fulfilled

Each SELECT statement within the union must have the same number of columns
Columns must also have similar data types
The columns of each SELECT statement must also be in the same order

score -1 · Answer 2

-1

The SELECT that make up the UNION must have the same number of columns and same names. Compare the structure of Like__post and post to see if there is not the problem.

answered by 14.12.2017 в 15:29