Is it possible to left align a sidewaytable to make use of the extra space at the left of it? Similar to the \LTleft\fill in longtable? I have not found a way to do this yet.
[Tex/LaTex] Left align sidewaystable
horizontal alignmentrotatingtables
Related Solutions
You have to add a new column to the flalign, and it seems there must be something in that column, so you can for example add an empty group, i.e. {}, in the second column.
You can add a new column by clicking the 
button on the table toolbar (I guess this pops up e.g. at the the bottom of the LyX window when you're in a flalign.), or using the keyboard shortcut Alt + MCI. That is, hold down Alt and press M, release both and press C followed by I.
In this column hit Ctrl + L (or Cmd + L in OSX) to add an ERT, and type a {. The closing brace is added automatically, I think.
Below is a screenshot of how it may appear in LyX, with the source view at the bottom, and below that a screenshot of the PDF.
You should add the fleqn option to your document class. Regardless, the following is the correct way of using eqnarray:
\documentclass[fleqn]{article}
\begin{document}
\begin{eqnarray}
\Psi_{1}(x,\lambda) & = & U(x,\lambda)e_{1}\label{eqn07}
\end{eqnarray}
\end{document}
You'll notice that the equation is left-aligned, although not flush with the left margin. To achieve this, add \setlength{\mathindent}{0pt} to the document preamble as well.
Note that you don't need eqnarray for a single equation. For this, the equation environment is sufficient. However, since the spacing of eqnarray is inferior to the regular math spacing, it might be better for consistency.
Best Answer
The
sidewaystableenvironment is a floating (and rotated) environment, but it does not in itself provide instructions on how to typeset tabular material. For that, you need to specify atabular,tabularx,tabular*, etc environment inside thesidewaystableenvironment. (In other words, thesidewaystableenvironment behaves exactly like the "ordinary"tableenvironment does, except that it rotates its contents and places them on a separate page.)For instance, to suppress the horizontal whitespace at the left and right-hand ends of a
tabularenvironment that has four columns (the first left-justified, the remaining three centered), you should specify something likeThe
@{}group tells LaTeX to suppress the horizontal whitespace.If you're using a
tabular*environment with a width equal to\textwidth, i.e., the full width of the text block, you could also specify